A coastal road is continuing to collapse in East Auckland while investigations continue on how to repair the slip site.

Extensive and deep cracking has appeared in a section of Marine Parade in Mellons Bay and a full lane is collapsing on the seaward side, leaving residents with only one lane in and out of the local road.

Five weeks after Auckland Transport came and covered the slip with black plastic sheeting, the slip has fallen further down the hillside, splitting the plastic, and in the past fortnight a large section of concrete kerbing on the seaward side has sheared off the road into the slip site.

“It’s just getting worse and worse…it’s scary,” said Kris Treneman, whose grandparents live opposite the slip.

Subsidence to the road on Marine Parade in Mellons Bay. Photo / Jason Oxenham.

Another neighbouring property owner, Garry Gorham, said the slip was creeping to the centreline of the road, inching closer to homes and falling further down the hillside.

He said the slip posed a risk to homes and if the authorities don’t do something about it there is a possibility the front houses could have issues in the future.

Gorham said he hoped AT had a plan of action to repair the road soon - “it’s certainly a danger”.

“If it gave away at any point it would be quite catastrophic,” he said.

An AT spokeswoman said the site is being monitored daily and additional ground investigation work was undertaken last week.

“We are currently reviewing the available repair options, with the goal of advancing to the detailed design phase this month,” she said.

Five weeks ago, AT said any repair would not be straightforward as there was still significant ground movement within the slip site, aggravated by six months of heavy rainfall.

Part of Marine Parade has collapsed and the plastic sheeting split since it was installed five weeks ago. Photo / Jason Oxenham.

Mark Treneman, who has lived across the road from the slip for 52 years, said the road started to split two months after it was patched this year.

He said engineers had visited the site drilling holes up to 30m deep to sea level, and it was his understanding piles would be put in along the length of the slip.

“Personally I’m not that concerned about it because AT is onto it. They have got good engineers who have been out here looking at things, they have certainly been very thorough and hope to have it finished by Christmas.

“If I have a concern, we don’t want to get to where we don’t have access at all. From what I know it is continuing to move,” he said.

Gorham and another resident at the end of Marine Parade were aware the slip is one of many being repaired throughout Auckland following the summer storm events, and conscious others are far worse off.

Bernard Orsman is an Auckland-based reporter who has been covering local government and transport since 1998. He joined the Herald in 1990 and worked in the parliamentary press gallery for six years.