Millions of mobile devices across Australia are expected to sound a loud emergency alarm today as the Federal Government conducts the first nationwide test of AusAlert, its new cell-broadcast public warning system.
The test alert will be transmitted at 2 pm AEST on Monday, July 27, equivalent to 1.30 pm in South Australia and the Northern Territory and midday in Western Australia. Most compatible smartphones, as well as some tablets and smartwatches, will vibrate, display a test notification and emit a siren-like sound for around 10 seconds.
The warning may override silent and “do not disturb” settings, although users will not be required to take any action. The message will state that it is a test and not a real emergency.
The national exercise represents the most significant test of AusAlert before the system is scheduled to become operational in October 2026.
Why Australia is replacing SMS warnings
AusAlert is designed to provide faster and more targeted emergency communications than Australia’s existing SMS-based Emergency Alert system.
Rather than sending individual text messages to selected phone numbers, AusAlert uses cell-broadcast technology to transmit a warning from mobile towers to every compatible device connected within a designated geographical area.
This means emergency authorities can send an alert to people physically located near a bushfire, flood, cyclone, tsunami, security threat or public health emergency without needing to know their phone numbers or residential addresses.
Messages are delivered through active 4G and 5G networks and are designed to arrive almost instantly, including when conventional mobile networks are congested.
The technology is also carrier-agnostic, meaning alerts can be received regardless of whether a device is connected through Telstra, Optus, Vodafone or another telecommunications provider. A compatible device may receive an alert even without a working SIM card, provided it can connect to an active supported network.
Cell-broadcast systems are already used for emergency warnings in more than 30 countries and are regarded by the National Emergency Management Agency as international best practice.
Faster, broader and more precise alerts
One of the central advantages of cell broadcast is its ability to deliver the same message to large numbers of devices simultaneously.
SMS systems generally send messages individually, which can create delays when authorities attempt to contact thousands or millions of people during a major emergency.
AusAlert instead broadcasts the warning across a dedicated communications channel. The message appears as a system-level notification rather than a conventional text and can be displayed over a locked screen or while a person is using another application.
Authorities can also define the geographical area in which the warning will appear, allowing messages to be directed at communities facing an immediate threat rather than entire states or territories.
That capability could become increasingly important during fast-moving natural disasters, where conditions can change rapidly and evacuation or shelter instructions must reach people within minutes.
National test follows community trials
The nationwide test follows community exercises conducted in nine locations across Australia during June.
Those trials were used to evaluate how effectively the system delivered alerts across different devices, networks, geographic environments and population centres.
Today’s test will dramatically increase the scale, with the alert being transmitted to compatible devices across the country at the same time.
The National Emergency Management Agency said testing was necessary to ensure AusAlert worked as intended before its planned October launch.
Authorities will examine factors including delivery performance, device compatibility and how the alert behaves across Australia’s mobile networks.
People who do not receive the warning may have an older or incompatible device, outdated operating software, no connection to an active 4G or 5G network or may be in an area with limited mobile coverage.
Users have been encouraged to keep device operating systems updated, although AusAlert should be treated as one component of Australia’s broader emergency communication network rather than the only source of information.
Radio, television, emergency service websites, social media and local warning systems will continue to play a role during disasters.
Privacy and tracking concerns addressed
Unlike mobile applications or location-based online services, AusAlert does not need to collect names, telephone numbers or personal location data before sending a warning.
The communication is one-way: a mobile tower broadcasts a message to devices in an area, but the system does not require those devices to respond or identify their owners.
That means authorities can warn tourists, commuters and other people temporarily located in an emergency zone, rather than only residents whose phone numbers are registered to addresses within the affected region.
The system’s geographical targeting is based on where the mobile towers transmit the alert, not on authorities tracking individual devices.
Safety warning for hidden phones
Domestic and family violence organisations have warned that the audible national test could expose hidden or secondary devices used by people experiencing abuse.
Because critical alerts can override silent settings, a concealed phone could make a sound even if the owner had deliberately muted notifications.
People concerned that an alert could compromise their safety have been advised to switch the device off or place it in flight or aeroplane mode before the test. Guidance published for the exercise recommends keeping affected devices switched off or in flight mode for 24 hours, because delivery times may vary according to network, device and location.
Drivers have also been advised not to handle or check their devices when the test arrives.
Preparing for the October rollout
AusAlert was developed as part of Australia’s effort to strengthen emergency communications following recommendations arising from major natural disasters, including the 2019–2020 Black Summer bushfires.
When operational, authorised emergency management agencies will be able to use the platform to issue warnings during natural disasters, public safety incidents, health emergencies and other serious threats.
The test may cause a brief and unusual interruption today, but it is intended to ensure the system performs reliably when Australians face a genuine emergency.
For the government and emergency authorities, the exercise will be an important opportunity to identify technical gaps before the high-risk summer disaster season — and before AusAlert becomes part of the country’s national warning infrastructure in October.