Experts say if a massive earthquake rattles the Kermadec trench, a tsunami could hit New Zealand in less than three hours.
To prepare for the possibility, Civil Defence is testing the country's tsunami readiness today.
More than 100 organisations and hundreds of staff right across New Zealand are involved in the exercise that will test responses in the immediate and long-term aftermath of a tsunami.
Civil Defence director Sarah Stuart-Black says it isn't a public drill, but does involve a lot of personnel.
"This is emergency services, local government, Government agencies, lifeline utilities all playing across the country," she said, speaking on Paul Henry.
It's been over 12 months in planning to make sure it's real, she said.
"The reality is there is a risk of tsunami, and New Zealand has not been free of tsunami in the past.
"Back in 1947 Gisborne was affected by a 10-metre high tsunami that was locally generated. That's within living memory. We know it can occur here."
Around 90 percent of New Zealanders know there's a risk but only a minority actually have an emergency kit ready.
Newshub.
