Civil Defence in Christchurch will test the city's tsunami warning siren system on Sunday morning.
The sirens will sound for one to two minues at 11am, as part of a twice-yearly testing of the system.
The sirens will only be heard within a few blocks of the beach along the coastline from Waimairi beach to Sumner, as these are the areas most at risk from a possible tsunami.
Civil Defence says residents are advised not to panic when they hear the siren.
Spokesperson Murray Sinclair says Christchurch City Council hopes residents in the areas most at risk will use the testing as a reminder they need to have an evacuation plan in place.