Best Phone System for a Small Office in Australia (2026)

This guide covers the three types of business phone systems available to small offices in 2026, what each one actually costs, and how to choose based on your team size, call patterns, and business requirements. Need to Know Comms is an independent Australian publishing project with direct experience in business communications infrastructure including NBN deployments, number porting, and cloud phone rollouts. By the end of this page, you'll be able to confidently evaluate your options, understand what questions to ask providers, and avoid the most common and costly mistakes small offices make when choosing a phone system.

The Three Types of Business Phone System

Every business phone system falls into one of three categories -- and for most small offices in 2026, the right answer is already clear. Traditional landlines are mostly gone (Telstra shut down the copper network in 2025). On-site PBX hardware is expensive, requires a technician to manage, and is overkill for a small team. Cloud phone systems are the modern default: lower cost, no hardware to manage, and works from anywhere.

Type 1: Traditional Landline (The Old Way)

Traditional landlines used copper wires running into your office from the public telephone network (PSTN). You paid line rental to Telstra or another carrier, and calls travelled over that physical wire.

This is not an option for new businesses in 2026. Australia's copper PSTN network was shut down in 2025. If your office had a traditional landline before NBN, it was migrated to a VoIP service (Voice over Internet Protocol) delivered over your NBN connection -- whether you knew it or not. In many cases, ISPs did this migration silently, plugging your existing analogue phone into the green phone port on your NBN modem. See the section on Australian considerations below for more on what that means.

Verdict on traditional landlines: Not available for new connections. If you're on a service delivered over the "green port" on your NBN modem, you're already on a basic VoIP service -- but one you don't control. This guide will help you understand what that means and what your alternatives are.

Type 2: On-Premise PBX (Hardware in Your Office)

A PBX (Private Branch Exchange) is the hardware that manages your phone system -- routing calls between extensions, managing voicemail, handling hold queues, and controlling call features. An on-premise PBX is a physical device installed in your office, typically in a server room or communications cabinet.

On-premise PBX systems were the standard for medium-to-large businesses for decades. They give you complete control over your phone infrastructure and can operate without internet access (using SIP trunks or ISDN lines for external calls). The trade-off is cost and complexity.

Upfront hardware cost: A properly specified on-premise PBX for a 5-10 seat office costs $3,000-$15,000 in hardware, installation, and initial configuration. Larger systems cost more. This is before any ongoing costs.

Ongoing costs: Maintenance contracts, firmware updates, additional licensing for features, and the cost of an IT professional or telephony specialist every time something needs to change or breaks.

Who on-premise PBX is right for: Businesses with specific compliance requirements (e.g., some healthcare environments), offices with unreliable internet connections where call continuity matters more than features, or businesses with existing on-premise investments they're not ready to retire. For most small offices with 1-20 staff on a standard NBN connection, on-premise PBX is neither necessary nor cost-effective. For a deeper comparison, see: Hosted PBX vs On-Premise PBX Australia.

Type 3: Cloud Phone System (The Modern Default)

A cloud phone system (also called hosted VoIP, hosted PBX, or cloud PBX) moves the PBX off your premises and into a data centre managed by your provider. Your phones connect to the system over your internet connection. Features are managed through a web-based admin portal. There's no hardware to buy, install, or maintain on-site beyond the phones themselves.

This is the category that has become the default choice for small offices globally and in Australia. The reasons are straightforward: low upfront cost, predictable monthly billing, a full feature set out of the box, and the ability to add users or change the system from a web browser.

The rest of this guide focuses on cloud phone systems, because that is the right starting point for the vast majority of small offices evaluating their phone system in 2026.

What a Cloud Phone System Actually Does

It helps to think of a cloud phone system as a phone exchange that lives on the internet instead of in your office. Here is what the key components actually do.

Your phone number (DID). A Direct Inward Dialling number is a regular phone number (02, 03, 07, 08 prefix) that points to your cloud phone account. When someone calls that number, your provider routes the call to your system. You can have one number or several. You can port your existing number across from your current provider.

Extensions. Each staff member who needs a phone gets an extension -- a number within your internal system (typically 3-4 digits). Extension 101 for reception, extension 102 for sales, and so on. Internal calls between extensions are free. External calls go out via your account's included call plan.

The auto-attendant. The automated greeting that answers calls and gives options ("press 1 for sales, press 2 for support"). Configured through the web portal. Professional, and included as standard with most plans.

Ring groups. A ring group makes multiple phones ring simultaneously when a call comes in. If you want all available staff to be able to answer the reception line, you put them all in a ring group. Whoever picks up first gets the call. This is the feature that lets a small team provide a professional phone experience without a dedicated receptionist at every moment.

Voicemail and voicemail-to-email. Standard voicemail plus the option to have voicemail messages transcribed or attached as an audio file and emailed to you. You never miss a message, even if you're not at your desk.

Call forwarding and after-hours routing. You can set rules for what happens to calls based on time of day. Outside business hours, route to voicemail. Or forward to a mobile. Or to a different auto-attendant message. This runs automatically, without someone manually changing a setting each day.

Softphone apps. Most providers offer a mobile app or desktop app that lets staff make and receive calls over your business phone system from their smartphone or laptop. Staff working from home, on the road, or between offices stay connected on their business number without being tethered to a desk phone.

Features Every Small Office Needs

Here is an honest breakdown of which features actually matter for a small office, and which ones you can safely ignore.

Features You Almost Certainly Need

• Multiple simultaneous calls (concurrent channels). The ability for two or more staff to be on the phone at the same time. If you only have one channel, the second caller gets a busy signal. Even a 2-person office should have at least 2 concurrent call channels.
• Voicemail to email. Voicemail messages delivered to your inbox as an audio file. Removes the need to dial in and retrieve messages manually.
• After-hours call routing. Automatic routing of calls to voicemail (or a mobile) outside your configured business hours.
• Number porting. The ability to bring your existing phone numbers to the new system. Any serious provider includes this.
• A basic auto-attendant. Even a simple "thanks for calling [business name], please hold while we connect you" message makes a small office sound professional and buys staff time to finish a task before answering.

Features That Are Useful But Situational

• Call recording. Essential for compliance-sensitive industries (finance, healthcare) and useful for training. Not needed for every business.
• 1300 or 1800 numbers. A national presence number can be important for certain businesses (national service, professional services). Add one if it matters to your brand. Not required for a local service business.
• CRM integration. Screen-popping caller details from your CRM when a call comes in. Valuable if you have a CRM and high inbound call volume. Usually an add-on at extra cost.
• Call queuing and hold music. Relevant if callers regularly wait on hold. For a 2-seat office with occasional simultaneous calls, a ring group is sufficient. For a business where callers genuinely queue, a proper queue with hold music matters.

Features Most Small Offices Don't Need

• Advanced contact centre features. Wallboards, live agent monitoring, skills-based routing, and callback scheduling are contact centre tools. A small office of 10 staff does not need a contact centre platform.
• Video conferencing through the phone system. Your team already has a tool for this (Teams, Zoom, Google Meet). Duplicating it through the phone system is usually redundant.
• Enterprise unified communications platforms. Unless your business has significant Microsoft 365 infrastructure and an IT team to manage it, an enterprise UC platform is overhead without return.

How Many Phone Lines Does a Small Office Actually Need?

"Lines" in a cloud phone context means concurrent call channels -- how many calls can be in progress simultaneously. This is different from extensions (how many people have a phone number).

A simple way to think about it: if 3 staff can all be on the phone at the same time, you need 3 concurrent channels. You might have 10 extensions but only 3 active calls at peak. Most cloud phone providers include a reasonable number of concurrent channels in standard plans -- but it's worth confirming this number before signing up.

A rough sizing guide:

• 1-3 staff: 2-3 concurrent channels is almost always sufficient
• 4-10 staff: 3-6 channels typically covers peak load
• 10-20 staff: 6-10 channels, depends heavily on call intensity of the role

High-call-volume roles (reception, inbound sales, support) need more channels than low-call-volume roles (developers, back-office staff). Use the Phone System Sizing Wizard to get a tailored recommendation based on your actual team structure.

What Does a Small Office Phone System Cost?

Cloud phone system pricing is structured per seat (per user) per month, with call plans either included or as an add-on. Prices below are AUD excluding GST, as is standard for business-to-business pricing in this category.

Entry-level plans (basic calling, voicemail, auto-attendant): $15-$30 per seat per month. Suitable for low-call-volume staff who mainly need to receive calls and have a professional presence.

Standard plans (unlimited local and national calls, mobile calls, full feature set): $30-$55 per seat per month. This is the most common tier for small office staff who make a moderate number of outbound calls.

Premium plans (call recording, CRM integration, advanced analytics): $50-$80 per seat per month. Relevant for roles with compliance requirements or high-value sales calls where recording and analytics matter.

Hardware costs. A business-grade SIP desk phone (the type that connects via Ethernet and registers directly with your cloud phone provider) costs $80-$200 per handset for a quality entry-level to mid-range unit. If staff use their mobile phone or a desktop app instead of a desk phone, hardware cost is zero.

Total cost example: 5-seat office, standard plan, desk phones for 3 staff.

• 5 seats at $40/seat/month: $200/month
• 3 desk phones at $120 each (one-time): $360
• First-year total: $2,760 (phone system costs only)

For an equivalent setup through a traditional carrier with comparable features, expect to pay more and get less flexibility. Use the VoIP Cost Calculator to model your specific scenario.

Desk Phones vs Mobiles and Laptops: What Should Your Staff Use?

Modern cloud phone systems support three endpoint types: desk phones (physical handsets on a desk), softphone apps on a mobile, and softphone apps on a desktop or laptop. You can mix all three on the same system.

Desk phones are best for: Reception roles, high-call-volume positions, anyone who needs to transfer calls or manage multiple lines simultaneously, and roles where a physical handset is more ergonomic over a long shift. SIP desk phones have physical buttons, which makes attended transfers and BLF (busy lamp field -- seeing which colleagues are on a call) much faster to operate than a software interface.

Mobile apps are best for: Staff who move around the office or between locations, remote workers, and anyone who doesn't need complex call management. The business number appears as caller ID when dialling out. Incoming calls ring on the mobile. Voicemail goes to email. It works.

Desktop apps are best for: Computer-based roles where the headset is already on and the screen is front-and-centre. Works well for sales and support roles who are already at their computer for the duration of the call.

A cost-effective approach for mixed teams: Give desk phones to reception and anyone who manages call flow. Give mobile apps to field staff and remote workers. Give desktop apps to support and sales staff who work at a computer all day. One phone system, three endpoint types, one consistent business number experience for your customers.

What Happens to Your Existing Phone Numbers?

Your existing phone numbers are portable. Number porting is the process of transferring your existing number from your current carrier to a new provider, and it is a legal right in Australia under ACMA (Australian Communications and Media Authority) regulations.

What is portable: Standard geographic numbers (02, 03, 07, 08 prefixes), mobile numbers, and 1300/1800 numbers can all be ported, though each category has slightly different processes and timelines.

What is NOT portable: Numbers tied to services rather than subscribers (some ISP-supplied numbers on basic NBN plans), and numbers that have already been released (cancelled) by your current carrier. Check portability before signing up with a new provider.

How porting works: Your new provider initiates the porting request. You provide your current account details (account number, service address, the number to be ported). The request goes through the carriers. Standard geographic numbers typically port in 5-10 business days. During this time, your existing service continues to work. Calls redirect to your new system when the port completes.

The most important rule: Do not cancel your existing service until porting is confirmed complete. Early cancellation can result in the number being released and lost permanently. For more detail, see our complete guide: Number Porting Australia.

How to Choose a Provider: What to Look For and What to Avoid

The cloud phone market is competitive, which is good news for small offices. But not all providers are equal.

What to look for:

• Australian-based support. When something goes wrong -- a call quality issue, a porting complication, a configuration question -- you want to speak to someone in Australia who understands the local environment. Ask specifically: is your support team based in Australia? What are the support hours?
• Month-to-month contracts. No serious, well-established provider should require a long-term contract for a cloud phone service. If they do, that is a negotiating tactic or a sign of low confidence in the product. Insist on month-to-month.
• Transparent pricing. Get a full itemised quote. What is the per-seat cost? What call plan is included? What is not included and costs extra? Are ring groups, auto-attendants, and voicemail included in the base plan or charged separately?
• Number porting experience. Ask how many ports the provider has managed in Australia and what their typical timeline is. A provider that struggles to answer this question clearly has limited porting experience.
• NBN awareness. A good provider will discuss your internet connection -- NBN connection type, upload speed, jitter -- and advise on QoS configuration. This shows they understand the AU deployment reality, not just the generic product.

Red flags:

• Long lock-in contracts with significant early termination fees
• Pricing that requires a phone call to get a quote (usually a sign of complex bundling and commission-based sales)
• No Australian-based support team
• Inability to port existing numbers or lack of clarity on the porting process
• Pushing enterprise-grade features (contact centre, advanced UC) on a small office that doesn't need them

Australian Businesses: What You Need to Know

NBN Requirements for VOIP Calls

Cloud phone systems depend entirely on your internet connection. In Australia, that means NBN for most offices. The good news is that modern NBN connections are more than capable of supporting business VOIP. The bad news is that NBN quality varies significantly between connection types, addresses, and times of day.

Bandwidth requirements. Each simultaneous call uses approximately 85-100Kbps of upload bandwidth (using the G.711 codec that most AU providers default to). A business with a maximum of 5 simultaneous calls needs 500Kbps of upload capacity dedicated to calls. Standard NBN 50 plans have 20Mbps upload -- more than sufficient. The constraint is rarely bandwidth.

Jitter and packet loss. Voice over IP is sensitive to jitter (variation in packet delivery timing) and packet loss. Even a 1-2% packet loss rate can produce noticeable audio degradation on calls. If your NBN connection has consistent jitter or packet loss, VOIP quality will suffer regardless of upload speed. A Quality of Service (QoS) setting on your router that prioritises voice traffic helps significantly.

NBN connection types. Fibre to the Premises (FTTP) and Hybrid Fibre Coaxial (HFC) generally provide the most stable base for VOIP. Fibre to the Node (FTTN) and Fibre to the Building (FTTB) can also work well when the copper length from the node to the office is short, but long copper runs introduce more jitter risk. Use the VoIP Bandwidth Calculator to assess your connection type and capacity.

The PSTN Shutdown and the Green Port Situation

Australia's copper PSTN network was shut down in 2025. This means that every "landline" in Australia is now delivered over NBN via VoIP. If your office has a phone plugged into the green port on the back of your NBN modem, you are on a VoIP service -- just not one you control or configured.

The ISP's modem contains a built-in ATA (Analog Telephone Adapter) that converts your analogue phone's signal to digital and connects it to the ISP's own VoIP service. The credentials are locked into the modem firmware. You cannot take a SIP desk phone (Yealink, Grandstream, Polycom) and plug it into the green port -- the port only accepts analogue phones. And you cannot extract the SIP credentials from the modem to use a different provider.

For small offices that have outgrown the basic ISP phone service, the path forward is to sign up with a dedicated cloud phone provider, have your number ported away from the ISP, and replace the analogue phone with either a SIP desk phone or softphone app. The ISP's phone service is then cancelled. See: How to Migrate from a Landline to VoIP in Australia and The PSTN Shutdown: What It Means for Your Business.

000 Emergency Calling Obligations

This is a non-negotiable requirement. Any business phone system that handles inbound and outbound calls must support 000 emergency calls. Under Australian regulations, VoIP providers are required to offer 000 calling capability, but there are two important caveats that many small offices don't know about.

First, 000 calls over VoIP only work when the internet connection is active. If your NBN connection is down, 000 calls will not go through via your cloud phone system. Always have a mobile phone available as a backup emergency calling device.

Second, the location accuracy of 000 calls made via VoIP is not always reliable. Emergency services use the registered address of the VoIP account. If staff are using the mobile softphone app from multiple locations (home, different offices), the registered address may not match their actual location. For staff who regularly take calls from locations other than the main office, ensure they understand this limitation. For more detail, see: 000 Emergency Calling on VoIP: What Australian Businesses Need to Know.

Australian Consumer Law and Telco Contracts

Australian Consumer Law (ACL) provides a baseline of protections for business telco customers, even in a B2B context for smaller businesses. The Telecommunications Consumer Protections (TCP) Code gives you rights around billing transparency, contract terms, and fault resolution.

Key protections relevant to small offices choosing a phone system:

• You have the right to a clear, plain-English description of all charges before signing a contract
• Early termination fees must be clearly disclosed upfront
• Fault resolution timeframes are regulated -- your provider cannot leave your service down indefinitely without consequence
• Number porting is your right -- a provider cannot prevent you from porting your number out when you leave

If you believe a provider is not meeting their TCP Code obligations, you can lodge a complaint with the TIO (Telecommunications Industry Ombudsman) at no cost.

What Most Businesses Get Wrong

Mistake 1: Starting with the handset instead of the phone system. The single most common error. A business owner decides they want a "proper business phone", buys a SIP desk phone online, then discovers they have no service to connect it to. The correct order is: choose your provider and plan, confirm compatibility, then select handsets based on the provider's recommendation. The handset is the last decision, not the first. See our full guide on VoIP vs traditional phone systems for the correct decision framework.

Mistake 2: Under-specifying concurrent channels. Buying a plan based on number of seats without confirming how many simultaneous calls the plan supports. A 5-seat plan with only 2 concurrent channels means the third caller gets a busy tone, even if 3 of your 5 staff are not currently on a call. Confirm concurrent channel count before signing up.

Mistake 3: Signing a long-term contract without comparing options. Multi-year contracts for cloud phone services are rarely necessary and often significantly more expensive over time when compared to month-to-month plans. The technology doesn't justify long lock-in -- providers who push 3-year contracts are often protecting their own retention metrics, not doing you a favour.

Mistake 4: Not testing call quality before committing. Most reputable providers offer a trial period or a demonstration call. Use it. Call in from a landline, from a mobile, from a busy connection and a quiet one. Test the auto-attendant, the ring groups, the voicemail. Quality issues that appear in a 10-minute trial won't surprise you after you've ported your numbers across.

Your Next Steps

Choosing a phone system doesn't have to take weeks. Here is a focused checklist.

1. Map your current phone usage. How many staff need a phone? How many simultaneous calls happen at peak? Do staff need to take calls when away from the office? Write it down.
2. List the features you actually need. Voicemail to email? After-hours routing? Ring groups? Call recording? Auto-attendant? Be specific. This becomes your shopping list.
3. Check your internet connection. Use the VoIP Bandwidth Calculator to confirm your NBN connection type and available upload capacity supports VOIP reliably.
4. Size your system properly. Use the Phone System Sizing Wizard to get a recommendation on seat count, channel count, and feature set based on your team structure.
5. Get a cost estimate. Use the VoIP Cost Calculator to model monthly costs at different plan levels.
6. Identify your existing numbers. Which numbers do you need to keep? Confirm they are portable before signing with a new provider.
7. Get a tailored recommendation. Once you have a clear picture of your requirements, get a recommendation from a specialist who can match you to the right provider and plan for your specific situation.

What is the difference between a cloud phone system and a traditional phone system?

A traditional phone system used dedicated copper lines and physical hardware (a PBX box) installed on your premises. A cloud phone system delivers the same functionality -- call routing, extensions, voicemail, auto-attendant -- over your internet connection, with the PBX hardware hosted by the provider in a data centre. For small offices, cloud phone systems are almost always cheaper, faster to deploy, easier to manage, and more flexible than traditional alternatives. The main exception is environments where internet reliability is genuinely poor, where an on-premise PBX may provide more resilience.

How many phone lines does a small office of 5 staff need?

The answer depends on how many calls happen simultaneously, not how many staff you have. In a typical small office where not everyone is on the phone constantly, 3-4 concurrent call channels handles peak load for 5 staff comfortably. If your office has a high-volume reception role or runs an inbound-heavy operation, you may need more. Use the Phone System Sizing Wizard to get a recommendation based on your actual call patterns.

Can I use my existing desk phones with a new cloud phone system?

It depends on your existing phones. If you have SIP-compatible desk phones (Yealink, Grandstream, Polycom, Cisco SPA series), they can often be reconfigured to register with a new cloud provider -- check with the provider for compatibility and whether they will assist with reconfiguration. If your existing phones are analogue handsets that plug into a green phone port on an NBN modem, they will not work directly with a cloud phone system and will need to be replaced with SIP handsets or softphone apps.

What internet connection do I need for a cloud phone system?

Any standard NBN connection with a stable upload speed and low jitter is sufficient for most small offices. Each simultaneous call uses approximately 85-100Kbps of upload bandwidth. Jitter (variation in packet delivery timing) has more impact on call quality than raw upload speed. NBN connection types in order of VOIP suitability: FTTP (best), HFC (good), FTTB (good if copper run is short), FTTN (adequate if copper run is short). If your current NBN connection has quality issues, fix those first -- a fast but unreliable internet connection will produce unreliable call quality. Use the VoIP Bandwidth Calculator to assess your connection.

Do cloud phone systems work during a power outage?

No. If the power goes out at your office, your router stops working, which means your cloud phone system stops receiving calls. This affects all cloud-based VOIP systems equally. The standard mitigation is call forwarding: configure your system to forward calls to a mobile number automatically if the VOIP connection drops. Most providers support this. Staff with mobiles can then continue to receive business calls during an outage. For businesses where continuous phone access is mission-critical, a 4G backup router is worth considering. This limitation applies equally to all NBN-based services -- the PSTN copper network that once worked during power outages no longer exists.

How long does it take to set up a cloud phone system for a small office?

The system configuration itself can typically be completed in a single day by a competent provider. The limiting factor is number porting -- transferring your existing numbers from your current carrier takes 5-10 business days for standard geographic numbers. During that time, your existing service continues to work. The practical timeline from decision to fully live on the new system is 2-3 weeks. If you're starting with new numbers (not porting existing ones), you can be fully live in 1-2 business days.

What is an on-premise PBX and does a small office need one?

An on-premise PBX is a physical device installed in your office that manages your phone system internally -- routing calls between extensions, handling voicemail, and managing features. In the cloud phone era, on-premise PBX is generally unnecessary for small offices. The upfront cost ($3,000-$15,000+ for hardware and installation) and ongoing maintenance overhead are not justified for a 1-20 seat office when a cloud phone system delivers equivalent features at a lower monthly cost with no hardware to manage. On-premise PBX remains appropriate for specific compliance environments or offices with genuinely poor internet reliability. For more detail, see: Hosted PBX vs On-Premise PBX Australia.

Are cloud phone systems secure?

Reputable cloud phone providers use encrypted SIP (SIPS/TLS) for call signalling and SRTP for media encryption, protecting calls from interception. The main security considerations are: choosing a provider with a clear security policy and encrypted transport, ensuring your office network is secure (particularly relevant if you're using the same network for phones and computers), and keeping firmware on desk phones updated. For most small offices, cloud phone systems are no less secure than on-premise alternatives -- and often more so, because the provider manages security updates and infrastructure hardening continuously.