Three dead and one missing as Auckland hit by record rainfall

"Our priority is to ensure that Aucklanders are safe, that they're housed and that they have access to the essential services that they need," Mr Hipkins said.

He said the city was in for a big clean-up and that people should remain indoors if possible.

He said a break in the weather could prove temporary, with more heavy rain predicted.

"This is an unprecedented event in recent memory," Mr Hipkins said.

Friday was the wettest day recorded in Auckland, according to weather agencies, as the amount of rain that would typically fall over the entire summer hit in a single day.

On Friday evening, more than six inches of rain fell in just three hours in some places.

The rain closed highways and poured into homes. Hundreds of people were stranded at Auckland Airport overnight after the airport stopped all flights and parts of the terminal were flooded.

Police said they found one man's body in a flooded culvert and another in a flooded carpark. They said fire and emergency crews found a third body after a landslide brought down a house in the suburb of Remuera.

One person remained missing after being swept away by floodwaters, police said.

Mr Hipkins said power had been restored to most places, although about 3,500 homes remained without electricity.

Video posted online showed chest-deep water in some places.

Politician Ricardo Menendez posted a video of water surging into houses. "We've just had to evacuate our home as the water was already rising rapidly and coming in aggressively," he tweeted.

Fire and Emergency New Zealand said crews had responded to more than 700 incidents across the region and staff had taken more than 2,000 emergency calls.

Air New Zealand said it resumed domestic flights in and out of Auckland on Saturday afternoon, but was not yet sure when international flights would resume.

In a series of updates on Twitter, Auckland Airport said people were able to leave the airport early on Saturday for their homes or accommodation after hundreds spent the night in the terminal.

The storm also caused an Elton John concert to be cancelled just before it was due to start on Friday night. A second concert that was planned at the stadium on Saturday night was also cancelled.

About 40,000 people were expected to attend each concert at Mount Smart Stadium. Thousands were already at the venue on Friday night when organisers decided to cancel not long before the singer was due to take the stage at 7.30pm local time.

Many concertgoers who had braved the conditions were frustrated the decision had not been made hours earlier.

Auckland Mayor Wayne Brown defended criticism that his office did not communicate the seriousness of the situation well and held off on declaring an emergency until about 9.30pm on Friday. He said the timing of the emergency declaration was guided by experts.