Don't be alarmed if you hear a tsunami siren tomorrow - Auckland Civil Defence is performing its twice-yearly checks on the warning system.

The tests, timed to coincide with the end of daylight savings, will take place at midday.

Auckland Civil Defence emergency management operations head Aaron Davis said the public should not be alarmed, and were not required to do anything.

"We run these tests to check operational performance and familiarise residents with the siren tones," he said.

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"The sirens are just one of a number of technology-based public warning systems that Auckland Civil Defence has in place for the entire region to better prepare for natural disasters."

The tsunami sirens are located in Rodney at Point Wells, Whangateau, Omaha and Waiwera.

In Waitakere, sirens are located at Bethells Beach Te Henga, Piha North, Piha South, Karekare, Whatipu, Little Huia, Huia, Te Atatu South, Harbour View Rd, Te Atatu Peninsula North, Westpark Marina, Hobsonville Airbase (Harrier Point) and Herald Island.

The test sequence will be three sets of tones, each signalling a specific action. They will sound for one minute each and there will be 15 seconds between each set. In an emergency, tones will sound for longer.

As well as being familiar with the siren tones, Mr Davis said people were also encouraged to subscribe to text message alerts, download the Auckland Civil Defence smartphone app or follow Civil Defence on Twitter and Facebook.