A tsunami warning will blare across parts of Auckland on Sunday, but it won't be accompanied by a destructive wave.
The region's twice-yearly tsunami siren test sounds at noon in the Rodney and Waitakere ward areas.
It'll consist of three sets of tones two minutes long.
"It's important to test the sirens to make sure they're working, and that Aucklanders know what they sound like," said Sarah Sinclair, Auckland emergency management acting director.
"There's no cause for alarm during the testing and the public isn't required to do anything."
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In a real emergency, the tones will last longer.
Messages will also be sent to people signed up to receive emergency alerts on their phones.
Like Fire and Emergency's push to check smoke alarms, the tsunami test is timed to coincide with the change in daylight saving.
- Alert (dash - dash - dot - dot) sounds for 15 minutes and indicates the threat of a tsunami. Evacuate beaches, prepare for full evacuation and monitor the radio or television for more information.
- Evacuate (dot - dot - dot) continuous bursts for 15 minutes indicates immediate evacuation to the nearest safe high ground. Please avoid using personal transport unless essential.
- All clear (continuous tone) sounds for 5 minutes indicate threat has passed. Return to premises if they have not been affected and follow directions of the emergency services if your area has been affected.