Eleven homes have been evacuated beneath a debris dam that formed in the Coromandel.

The district has been hit by several heavy rain storms in recent weeks, causing slips, flooding and damaging roads.

Thames-Coromandel Mayor Len Salt says there had been a slip and some of the farmland behind the small settlement of Koputauaki had slumped.

"It's dragged some debris and some soil down into a gully, you've got some trees and bits of vegetation which have built up and blocked that and you've got a build-up of water behind it."

As the water built up and there was more rain there was concern it could let go causing a real danger to the people living below it, he says.

"What we've done is as a precautionary measure we've evacuated about 11 families from houses down in that area."

Helicopters with monsoon buckets worked to clear water from the dam above community on Monday, he says.

"They were quite successful in clearing some of that blockage and letting some of that water go."

But he says the team was not happy that enough water had been drained and were working through other options over the next couple of days to completely clear the debris dam.

Generally the Coromandel district was in reasonable shape, Salt says.

The Thames Coast Road is open, the south-eastern access to the peninsula through Paeroa, Waihi and Whangamata is open, he says.

The only roads to remain fully closed are State Highway 25A and the Tapu Coroglen Road, he says.

Salt visited SH25A last Thursday with Emergency Management Minister Kieran McAnulty and described how it looked.

"Imagine standing on the edge of our version of the Grand Canyon and looking down, it was pretty impressive ... it's a long way down, a lot of material and vegetation dropped down and still some water coming through, so you could see where there's been an undermining of that."

Salt says he was very impressed with the work being done by Waka Kotahi and geotech teams working on SH25A.

- RNZ.