Civil Defence is giving notice about their plans to test the new mobile emergency alert system in a couple of weeks time.
The forewarning comes after a rude awakening last month where text messages were accidently sent out in the very early hours of the morning.
This test is set to take place between 6pm and 7pm on Sunday the 26th.
Enabled phones will emit a penetrating warning sound, and show a test warning message.
Using cell broadcast technology, there's no need to sign up or download an app, and you can't opt out.
Civil Defence Minister Kris Faafoi warns that not everyone will get them.
"About 30 per cent of phones, or about two million phones, will be able to get them. Over time over the next three years we think that will get through to about 70 per cent."
Faafoi asks that those who can receive the warnings, spread the word to family and neighbours - in a real emergency.
The alerts are another important warning tool, along with the radio and TV broadcasts, reminds Faafoi.