Auckland starts clean-up after deadly flash floods

The clean-up in Auckland has begun after torrential rains brought flash flooding and evacuations, with three people confirmed dead and one missing in the widespread inundation.

Key points:Emergency crews responded to more than 700 incidents and took more than 2,000 callsInternational flights from Auckland will resume New Zealand's national weather forecaster warns of more rain and flooding

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.

Prime Minister Chris Hipkins, less than a week in office, flew by helicopter over the city before touring flood-hit homes.

"The level of devastation in some areas is considerable," Mr Hipkins said, describing the event as "unprecedented" in recent memory.

"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."

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.

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

Daylight revealed the impact of the storm, caused by warm air descending from the tropics, sparking heavy rain and thunderstorms, said Auckland Emergency Management.

Mr Hipkins travelled to Auckland by military aircraft on Saturday.(AP: Ryan Benton/pool)

"Auckland was clobbered on Friday – Auckland's wettest day on record – and today we start the clean-up," the agency's duty controller Andrew Clark said.

He urge caution for residents returning home and advised them to survey flood damage.

More severe impacts expected as rain returns

Police said they found one man's body in a flooded culvert and another in a flooded car park.

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.

Cars almost submerged in Auckland amid flooding.

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.

Mr Mosby said crews had rescued 126 people who were trapped in houses or cars, or who had been involved in vehicle crashes.

City rainfall records were broken, with Auckland Airport logging 249 millimetres in the 24 hours to 9am on Saturday (local time), beating the 1985 high of 161.8mm.

Some local flights resumed at Auckland Airport, which had closed domestic and international operations on Friday.

Air New Zealand said its domestic flights in and out of Auckland had resumed, and international flights out of Auckland would resume on Sunday (local time).

Air New Zealand said 12 of its international flights due into Auckland had been diverted overnight.

While heavy rain had eased, further downpours were possible on Sunday, the national weather forecaster said, adding the impact was "expected to be severe and wide reaching because of the saturated ground".

"More flooding will occur through many northern regions in the coming days," it warned.

On Friday, social media showed firefighters, police and defence force staff rescuing stranded people from flooded homes using ropes and rescue boats.

The flooding forced cancellations of British pop star Elton John's concerts in the city, which had been scheduled for Friday and Saturday nights.

About 40,000 people were expected to attend each concert at Mt Smart Stadium.

Thousands were already at the venue on Friday night when organisers decided to cancel not long before John was due to take the stage at 7:30pm (local time).

Many concertgoers were frustrated the decision hadn't been made hours earlier.

Video shows extent of flooding at Auckland airport amid heavy rain

Reuters/AP/ABC