Photos: Evacuations, flight cancellations after flooding in upper South Island

Several South Island towns have been cut off and multiple flights have been cancelled as torrential rain lashes parts of the country.

The New Zealand Defence Force knock on doors telling residents to evacuate in Buller. Source: New Zealand Defence Force

High river levels combined with flooding, fallen trees and slips have largely halted travel through the regions, with access to Tākaka, Collingwood and Murchison blocked off in Tasman.

A ute is engulfed by the Buller River as a dumping of rain forces water levels to rise. Source: Jules Anderson

More than 820 people were evacuated from low-lying areas last night, with the majority spending the night in emergency shelters set up in Westport.

A man out on a run as waves crash along Tamaki Drive, in Auckland. Source: Supplied / Matthew Davison

It comes as MetService announces an extension to the rare red warning in place through to 3am tomorrow, with more flooding likely.

The New Zealand Defence Force (NZDF) evacuate residents in Buller. Source: New Zealand Defence Force

Waka Kotahi NZTA is urging all motorists in the area to avoid unnecessary travel, particularly through Nelson and Marlborough, with more rain on its way in the coming hours.

An aerial image of flooding across Buller, photographed by Buller District Mayor Jamie Cleine. Source: Jamie Cleine

A state of emergency has since been issued for Marlborough, with residents of the Lower Terrace in Renwick asked to evacuate their properties and stay with family or friends for the next 24 hours, Marlborough Deputy Mayor Nadine Taylor said today in a statement.

Occupants of a campervan being airlifted to safety via helicopter amid rising floodwaters in the Motueka River, Nelson. Source: Supplied

"Our crews are working as hard as they can but these slips and debris will take time to clean up and flood waters take time to subside," spokesperson Tresca Forrester said.

The New Zealand Defence Force (NZDF) work to evacuate residents as torrential rain batters Buller. Source: New Zealand Defence Force

"Please do not drive if you do not have to or delay your journey until later today and check highways then."

A raging Buller River flows through Westport after a dumping of rain. Source: Anita Kay

For full details on road closures, check the NZTA website.

Intense flooding on State Highway 6, Havelock. Source: Supplied

Meanwhile, at least four flights have been cancelled out of Nelson Airport as of lunchtime today, with a further two services inbound also grounded.

Flooding in a vineyard in Blenheim. Source: 1 NEWS

Some flights from Auckland to Whangārei, New Plymouth, Palmerston North, Blenheim and other centres have been cancelled.

Flooding in Blenheim. Source: 1 NEWS

There are significant delays on flights and some cancellations into and out of the capital today with high winds causing disruption.