New Zealand's ability to respond to a major tsunami is going to be tested.
Civil Defence Minister Nikki Kaye says it will run over three separate days, with the first on Wednesday which will focus on preparations during the period between an alert and the first waves hitting the coast.
On September 14 the focus will shift to response after the tsunami has hit, and on September 28 management of longer-term recovery will be tested.
Ms Kaye says more than 100 organisations and several hundred staff will take part in Exercise Tangaroa.
"While there will be some public involvement, this exercise will mainly involve the agencies who would be part of a tsunami response," she said on Monday.
"A major tsunami would require a simultaneous national, regional and local response, so those involved will include central, regional and local government staff as well as emergency services, lifeline utilities such as power and telecommunications, and even embassies and high commissions."