Authorities say three people have died and at least one is missing after record levels of rainfall pounded New Zealand's largest city, causing widespread disruption.
Prime Minister Chris Hipkins flew to Auckland on a military plane after a state of emergency was declared in the region.
"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," 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 forecast.
"This is an unprecedented event in recent memory," Hipkins said.
Friday was the wettest day ever 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 15 centimetres 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 car park.
They said one person was missing after being swept away by floodwaters while another remained unaccounted for after a landslide brought down a house in the suburb of Remuera.
Hipkins later said three people had been confirmed dead while at least one remained missing. He 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.
Lawmaker 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.
"We had every available career and volunteer crew on the road responding to the most serious events," said district manager Brad Mosby.
Mosby said crews had rescued 126 people who were trapped in houses or cars, or who had been involved in vehicle crashes.
Air New Zealand said it resumed domestic flights in and out of Auckland on Saturday afternoon, but wasn't 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 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 Friday night. A second concert by John that was planned at the stadium on Saturday night was also scrapped.
About 40,000 people were expected to attend each concert at Mt Smart Stadium. Thousands were already at the venue Friday night when organisers decided to cancel not long before John was due to take the stage at 7.30pm.
Many concertgoers who had braved the conditions were frustrated the decision hadn't 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.
"We will review everything that took place," Brown said. "We've got to make sure we had the coordination, and the consultation with the public, correct."
Australian Associated Press
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