Auckland Emergency Management may fly supplies in to areas of the region's west coast with no power or road access.

Around 300 homes in Muriwai are in peril from slips, while 20 homes were evacuated in Piha yesterday and five homes in Karekare have been destroyed in slips.

Karekare resident and former Waitākere City mayor Sir Bob Harvey said they are completely cut off, with 10 visible major slips.

They have been walking in food supplies, Sir Bob said.

"We've got a system going where we can drive down to the slips and cart them round the edges. It's a bit of a mule trip over a hump and bump through the bush and we can take cartons of food down."

It was an emotional time for residents who are dealing with the trauma of losing houses and the danger of slips, he said.

"Five [houses] have come down including a terrific house up on the hill built by a beautiful loving couple and they were in it when it started to move. I guess of all the houses we thought wouldn't move, this one did. They are now safe."

Sir Bob said another house resembled "matchwood" after collapsing in a slip - its occupants, a woman and her two children, now safe.

A house collapsed after a slip on Rayner Road, Piha, west of Auckland. Photo: Supplied

The Surf Lifesaving club has become a lifeline, he said.

"The whole of the Karekare community is truly cut off, no one can get down and no one can get up so the Surf Club has become a vital communication and comfort stop."

It has a power generator and 30 bunk beds, all full.

"We have adequate accommodation. I didn't realise it would be so emotional, we're kind of traumatised in a way. We're going to suffer from post Gabrielle trauma it's going to affect us for a long time."

Auckland Council director of regulatory services Craig Hobbs said they still did not yet know the full extent of damage in the coastal communities.