Trucks stopped in Taihape. Photo: Supplied

Cars blocked by a slip in rural Taihape are now free after a local farmer cleared a path for them with his tractor.

About 20 cars were stuck for several hours between a flood and a slip in the remote area of Turakina Valley Rd where there was no cell coverage.

Rangitikei Mayor Andy Watson says the cars were able to be driven out and he believed they were now heading to Taihape.

Watson previously said he understood it was a local farmer who raised the alarm, calling emergency services to report what he could see.

It had been very hard to get information, he said.

It appears the cars took a back route after State Highway 1 was closed.

"They've found flood water that was too deep to drive through then slip has come down behind them and effectively blocked their path," he said.

Residents in the wider district have told RNZ there are trees blocking may roads, with people not able to get to work.

State Highway 1 has been closed around Taihape.

Watson said some of the roads the cars took would normally only see "half a dozen" cars a day, he said.

Rangitikei District Council said contractors were working to clear debris, and it was working with Civil Defence on a response to the situation.

Police said they were notified at 12.30pm.

St John said it had so far not been required.

Establishing communication the priority

Manawatū-Whanganui Civil Defence said its first priority was to establish communication with those who were trapped.

State Highway 1 was closed between Hunterville and Waiouru and people should not use Turakina Valley Rd as a detour, it said.

Many other local roads were also closed.

People should avoid non-essential travel because the roads were treacherous from fallen trees and the possibility for landslides.

Winiata Marae opens to stranded travellers

About 80 people are sheltering at Winiata Marae, in Taihape, which has opened to stranded travellers.

The marae's chairman Jordan Winiata said they were travellers who had become stranded, unable to reach their destinations.

"They're stranded because of what's happening on the highways, we've got some InterCity buses, just multiple travellers that would have been going from A to B that unfortunately have been caught in between the roads being open and closed."

He said the marae was preparing to host those stranded overnight and had capacity for 300.

Winiata said the power was out at the marae, but they had a generator and running water and gas for cooking.