Civil Defence Otago emergency management controller Chris Hawker said a tsunami was one of the major threats to coastal areas in the region.
"The scenario of an earthquake in the Kermadec Trench, generating a tsunami that takes less than three hours to reach New Zealand, is a credible projection."
He said Emergency Management Otago would be operating from the Emergency Co-ordination Centre, based at the Otago Regional Council, for the duration of the day-long exercise.
The Waitaki District, Dunedin City and Clutha District Councils would each activate their own local responses as they would in the event of a real tsunami.
The landlocked Queenstown Lakes District and Central Otago District Councils would contribute personnel for the exercise, he said.
Partner agencies, including the Southern District Health Board, would also join the exercise.
"It’s a very good opportunity for us to simulate the response that we would need to make in the event of an actual tsunami, and to train our personnel in the systems and processes that we would use."
More than 100 organisations and several hundred staff nationwide will participate in today’s exercise.Civil Defence Minister Nikki Kaye said the exercise would take place on three separate days in August and September.
The exercise would start today, with a focus on the actions taken between when the tsunami alert was received and when the first waves hit.
On September 14, the second exercise would focus on the response after the tsunami had hit.
Then, on September 28, the third exercise would test the management of the longer-term recovery after the tsunami, she said.
"While there will be some public involvement, this exercise will mainly involve the agencies who would be part of a tsunami response, unlike our national earthquake drill, ShakeOut, which has a broader public participation.
"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 companies, and even embassies and high commissions.
"Exercise Tangaroa has an important role to play in helping us identify any gaps in tsunami warning, response and recovery in New Zealand.
"The exercise will also inform the shape of future Civil Defence emergency management and government work programmes."
