Tsunami sirens will sound along the Canterbury coastline and Northland this morning as civil defence staff carry out tests.
Christchurch City Council said sirens will sound for three minutes at 11am, from Brooklands to Taylors Mistake.
The sirens would be heard only within a few blocks from the beach, as these were the areas most at risk from a tsunami, the council said.
In the event of a real tsunami the sirens would sound for more than 10 minutes.
Tsunami sirens in Northland will also be tested this morning.
Northland Civil Defence said more than 150 sirens around the region would sound at 10am.