Record rainfall has hammered through the West Coast with an elderly woman's body found after she was swept away by the flood waters and a bridge left in ruins.

In the last 48 hours, Cropp Waterfall has recorded 1086mm of rain - the highest level for that time period on record, Niwa Weather says.

The heavy rainfall has eased in the area and was now making its way through Wellington and Taranaki. People in the area are being advised to keep up to date with the forecasts.

Police said the body of Gloria Reardon-Hirst, 66, of Arahura Valley was found in the Arahura Valley, north of Hokitika this morning.

"An initial scene investigation appears that the woman got out of the vehicle she was driving and tried to cross the flood waters on foot."

A police spokeswoman said the woman had then been swept away in the strong-flowing current of surface flooding on Arahura Valley Rd.

"The investigation is ongoing, and her death will be referred to the coroner. Our thoughts are with the family at this sad time," the spokeswoman said.

A large section of road has been completely washed away. Photo / Wayne Costello, DOC

The extreme weather front caused major flooding and demolished a bridge on the West Coast, closed major roads and schools and forced evacuations.

A state of emergency remains in place in Westland and is expected to be lifted "today or tomorrow".

Multiple roads remain closed on the West Coast due to the damage caused by the floods. However, State Highway 73 from Otira to Kumara Junction has been reopened.

An update on State Highway 73 from Arthurs Pass to Jacksons will be given at 4pm.

Prime Minister Jacinda Ardern said she had been briefed on the flooding and officials were working as quickly as they could.

"And the NZTA, particularly to restore links where there has been that lost bridge.

"I'm advised seven to 10 days until that connection is restored," Ardern said.

Aerial photos taken for the Department of Conservation reveal the staggering impact of the flood waters - washing away a bridge and gouging giant chunks out of roads.

The flood waters have swamped planes in the area. Photo / Wayne Costello, DOC

MetService meteorologist Kyle Lee said most weather stations along the coast had recorded just under 200mm since the rain event started on late Sunday to early Monday.

Stations inland were hitting well above 200mm, and one station even recording around 1000mm.

Tourists were kept in the small West Coast town yesterday with treacherous road conditions also north to Hokitika.

Farther north, Arthur's Pass remained blocked today by two slips, with updates due at midday, leaving the only way out of the West Coast region several hours' drive north and through the Lewis Pass.

With many travellers planning to head south from Franz Josef to the Wanaka and Queenstown area, today they would have to make new plans.

The washed away chunk of highway. Photo / Wayne Costello, DOC

Flooding hasn't only been restricted to rivers. Surface flooding has also resulted in road and school closures throughout the region.

The Insurance Council of New Zealand (ICNZ) has put out storm preparation and flood recovery tips for those affected the severe wet weather currently battering the West Coast.

ICNZ chief executive Tim Grafton said it was important communities looked out for each other in times like these.

"Check on your neighbours and friends and make your properties as storm-safe as possible without putting anyone's personal safety at risk."