PM John Key says the Government expects to announce measures for a national disaster warning system which will send out an alert to every cellphone in the country.

Key said the Government had been working on it for some time prior to the most recent spate of earthquakes and there was money set aside in the Budget for a national alerting system in disasters, similar to those used in other countries.

"My understanding was that it was certainly turning out to be more expensive than we thought and we've been shopping around trying to see if we can get a better alternative.

"There is no doubt that where we will be going is national alerting. It doesn't matter if your cellphone is on or not, it's not a matter of whether they know about your cellphone or not, it just blasts a message out to everyone. That's a strong positive."

Advertisement

However, he said when it came to tsunami people in low lying areas should move to higher ground immediately after a long, strong earthquake rather than wait.

He dismissed some claims that it could be done for less than $1 million. "We've never seen anything like that. We're in the tens of millions."

He said care had to be taken not to overuse such systems or people would stop acting on the warnings.

He said the latest quakes did raise questions around tsunami warnings and why some buildings had not withstood the quake as well as expected.

"There are some questions that need answered and that is always the case when you get a natural disaster."

He did not believe a Royal Commission was required, but other inquiries were underway such as the inquiry into the failing of the Statistics NZ building.

Civil Defence would also review what had and had not worked.