New Zealand has declared a state of emergency in its capital city Wellington as torrential rain and flash flooding drenched the country's North Island.

Footage online shows vehicles submerged, trees uprooted and houses hit by landslides. Wellington received a record 77mm (3in) of rain in less than an hour on Monday, said mayor Andrew Little.

Local authorities advised residents to hunker down, with rain forecast for the next day and a half. Some flights at Wellington Airport have been cancelled and several schools have shut their campuses.

More than a dozen people have been evacuated while a 60-year-old man in the Karori suburb has been reported missing. No fatalities have been reported so far.

This series of flash floods comes less than a week after Cyclone Vaianu swept through the North Island last weekend.

Research over the years have shown that climate change has made extreme weather events, including floods, more common and more intense around the world.

"The wild weather continues. We've had flooding, slips and evacuations... The flooding has been strong enough to move cars, and many manhole covers have been lifted," Little said in a video published on his Facebook page.

In the suburb of Kingston, a resident told Radio New Zealand (RNZ) that he had tried to escape on the back of his neighbour's motorbike after a landslide buried a nearby road in the early hours of Monday.

"It's definitely a big event," he said. "You wouldn't have wanted to be under it, it wouldn't have been survivable."

Another resident in the suburb of Mornington said his garden had been "inundated with water, you couldn't see the grass or anything". There was a "huge deluge, flow, river in fact, flowing through the garden", he told RNZ.

Mark Mitchell, the minister for emergency management and recovery, said they were expecting the "worst of the weather" later on Monday evening.

"If you are in the Wellington region, be prepared," he said in a post on Facebook. "If you are going to evacuate make those decisions early and keep yourself updated with information."

The emergency management office for the Wellington region has advised residents to cut or delay all non-essential travel, and for those residing in low-lying or flood-prone areas to consider relocating to their friends' and families' for at least the next 24 hours.

The Wellington City Mission has been set up for those who need shelter, the office added.