By 3 News online staff
A review of tsunami hazards around New Zealand has found the maximum size of a tsunami is bigger than first thought, but is no more likely to happen.
The 222-page report released by Civil Defence today, says the areas where a local or regional tsunami pose a greater risk that previously understood include the coast of Northland, the north-west part of Auckland, Great Barrier Island, Coromandel Peninsula and the Bay of Plenty.
The east cape of the North Island, parts of the Wairarapa coast, Southland, Stewart Island, Fiordland and Westland are also included.
Civil Defence also says a large tsunami generated "very close" to the country would arrive before an official warning could be issued or sirens activated.
"People must know what if they are at the coast and feel a strong earthquake or a weak earthquake which lasts a minute or longer, then get to high ground or go inland.
"Do not wait for an official warning," the ministry says.
Civil Defence director John Hamilton says a tsunami from a local earthquake would reach land in less than an hour, while a regional quake would arrive between one and three hours.
The Ministry commissioned GNS Science to conduct the review to update research published in 2005.
The review took into account large earthquakes around the world which were bigger than previously thought possible including in the Indian Ocean in 2004, the South Pacific in 2009 and the tsunamis in Japan in 2011.
There was a similar tsunami which hit Japan in AD869 which indicated the interval between the biggest quakes there is more than 1000 years.
But Civil Defence says it is difficult to provide the same data for New Zealand because of its relatively brief historical record of 200 years.
During that time the country has had around 10 tsunamis which were five metres or higher.