Northland's six-monthly tsunami siren test will take place at the end of daylight saving on Sunday, April 3.
The network of more than 200 outdoor tsunami sirens in coastal communities, from Te Hapua in the north to Mangawhai in the south and Ruawai in the west, is checked twice a year, coinciding with the start and finish of daylight saving.
The sirens sound twice - at 10am for 10 minutes and again at 10.30am for 30 seconds - and will be monitored for any faults.
Indoor sirens will be tested at the same time as the outdoor network. Test alerts will also be sent to users of the Red Cross Hazard app, which can be downloaded free.
Northland Civil Defence Emergency Management Group spokeswoman Claire Nyberg said people should also be aware of the risk of local source tsunami - those generated on or close to the coast - which could arrive ahead of any official warning.
"Everyone who spends time on the coast needs to know the natural warning signs of tsunami – a strong earthquake that is hard to stand up in or one that lasts longer than a minute, or out-of-the-ordinary sea behaviour such as sudden rise or fall and/or unusual noise."
