Civil Defence says an exercise to test the national response to a potentially destructive tsunami from the Pacific Ocean has gone smoothly.
Known as Tangaroa, the exercise tested and evaluated response procedures when a mock tsunami warning is issued.
Sixteen regional civil defence teams and more than 100 agencies took part on Wednesday.
The exercise used new computer modelling from GNS Science to accurately identify the threat to regions.
Civil Defence national controller David Coetzee says it is the first time the modelling has been put to the test, and it worked well. He said the science will be used in real warning situations in the future.
Mr Coetzee said Civil Defence teams continued the tsunami exercise until about 7pm, which is just after the first waves were due to hit.
The Ministry of Civil Defence says while it is a nation-wide exercise, participation has been at the discretion of individual local bodies.
Director John Hamilton said it included the testing of warning sirens and evacuations of some facilities, including a school in Wellington.