Hundreds of New Zealanders who raced to beaches yesterday to watch a potentially catastrophic tsunami were "stupid", says Civil Defence Minister John Carter.

But his own Civil Defence officials are in the firing line from the public because of their performance at the weekend.

And claims are being made that Kiwis are becoming immune to frequent tsunami warnings.

At least 300 people are dead after a powerful Chilean earthquake - the fifth biggest recorded - spawned the tsunami that sped across the Pacific yesterday.

Despite warnings in almost 50 countries, and the evacuation of hundreds of thousands of people, the tsunami threat came to little.

In New Zealand, people ignored official warnings and raced to beaches to watch the tsunami surge towards land.

"What people need to understand is if they go and watch for a tsunami, it might be the last thing they ever do," said Mr Carter.

"This is a dangerous, dangerous thing. In the main it's been good, but we always get a few stupid people."

Despite a Civil Defence blitz on radio, internet and television warning of the risk of 1m to 3m waves hitting the east and west coasts, many New Zealanders refused to let their beach plans for the last day of summer be interrupted.

Others went to the coast specifically to see the tsunami.

One Auckland beachgoer said it was a case of crying wolf. "There's been so many warnings you think, 'Ah, it's just another one'."

An hour after Saturday night's earthquake, about 8.30pm, Civil Defence said there was no risk of a tsunami coming to New Zealand.

But later, at 11.20pm, the organisation issued a warning to stay away from beaches.

Weatherwatch analyst Philip Duncan said the first advisory was a serious mistake.

"Towards midnight, a warning was finally issued. This was unacceptable, in my view. It was far too late and explains why so many people on the beaches on Sunday morning had no clue a tsunami was even coming."

At Takapuna Beach, the warnings didn't keep 76-year-old Eugenia Patras out of the water.

Geonet had predicted waves would hit Auckland's east coast beaches at 10.52am after their 9600km journey from Chile.

At 10.50am Mrs Patras, on holiday from Wellington, was washing sand off her feet.

"I missed yesterday's swim, so I thought I'll have a quick swim," she said. "I made sure I was out on time."

Although the beach was quieter than usual, Mrs Patras' attitude to the risk was shared by many as North Shore boaties, waka ama paddlers and the Piha women's surf crew went out on the water.

Around the country, the story was repeated.

Annabelle Harris took her son Jack Calvert, 9, to look for the waves from the streets overlooking Lyttelton Harbour, near Christchurch. She felt she was safe watching from higher ground.

"If we'd had to scramble up the bank, I'm sure we could do that."

Director of Civil Defence John Hamilton said people were being naive.

"It's not an uncommon attitude - 'we'll be right' and 'I've done it before, I can do it again'. Our challenge is to make people aware of the risks."

Mr Hamilton denied Civil Defence could be accused of crying wolf.

"We are dealing with Mother Nature - and human nature - and both are unpredictable.

"I'd sooner be accused of crying wolf and putting out warnings that can be cancelled rather than the other way."

A North Shore City councillor says the council's tsunami-alert service sent out an automated message to residents' phones yesterday morning telling them the warning was a practice.

"It was only when I tuned into the 8 o'clock radio news that I realised the phone message was incorrect," said Chris Darby, who lives at Stanley Pt

"The failure by Civil Defence to load the correct message could have led to dire consequences. There was not even a follow-up correcting the error."

- additional reporting: NZPA