The country's readiness for a major tsunami is being tested in the first stage of a major civil defence exercise.
The exercise is based on the scenario of a tsunami generated by an earthquake in the Kermadec trench and taking less than three hours to reach New Zealand.
While there will be some public involvement, the exercise mainly involves the agencies who would be part of a tsunami response.
The exercise is taking place over three separate days during the next month.
Today will focus on preparations during the time between when an alert is received and the first waves hit.
The National Crisis Management Centre in the basement of the Beehive is being activated and with staff from relevant agencies called in as they would be during a real emergency.