The Australian Government plans to test its new national warning system AusAlert on Monday, ahead of a planned national roll out in October.

The national warning system uses cell-broadcast technology to send emergency messages to compatible mobile devices.

"Before it launches in October 2026, we need to test the system to make sure it works as intended," the government said in a statement shared widely across social media.

"On Monday, July 27, at around 2:00 pm AEST, a test AusAlert will be sent to all compatible mobile devices in the country at the same time," the statement said.

"This is called the AusAlert national test. It will be a Critical Alert, which means mobile devices will vibrate, make a loud siren-like warning sound that lasts about 10 seconds, and show an AusAlert test message."

The AusAlert website says a message will appear on device screens, clearly indicating it is an AusAlert test. Exactly how the message will appear on your own devices will depend on your device types and operating systems. An example is pictured. However, it is important to know that older devices or different operating systems may receive a different type of message.

"If you have an older device or use an alternate operating system (e.g. GrapheneOS, LineageOS), you may get a test alert with the heading ‘Presidential Alert’ or ‘Extreme Threat Alert’," the AusAlert website states.

"The content of the alert will be the same. This is because some older devices don't follow Australian Standards and will display an American or international alert heading instead of the Australian 'AusAlert'.

It is also important to know that Critical Alerts override ‘silent’ or ‘do not disturb’ functions on compatible devices.

"If the AusAlert national test will disrupt you or cause you or someone you know to feel unsafe, turn mobile devices off or switch them to ‘aeroplane mode’ before the scheduled test time and leave them off for at least one hour," the government has advised.

For more information on the AusAlert system, including an example how the alert will sound on the day of the test, visit ausalert.gov.au.