Birkenhead slip widens, swallows machinery

A slip in Birkenhead has widened, swallowing a piece of machinery and sending workers scattering this afternoon, a local witness says.

The slip took 25 car parks - about 50m of carpark land - in October, and Auckland Council has been monitoring the site by Rawene Reserve ever since.

Auckland Transport spokesman Mark Hannan confirmed a piece of machinery has fallen into the pit created by the slip this afternoon.

Another slip hit the carpark in Rawene Rd, Birkenhead about 5pm, he said.

"The area has been closed for several weeks after an earlier issue with major subsidence.

"A piece of equipment has been carried down the slip. No one has been injured."

Auckland Transport and contractors were on site this evening to secure the area and investigate the incident.

WorkSafe NZ has been advised.

Local resident Graham Tucker, who lives in Mokoia Ridge Apartments overlooking the slip, saw it widen about 4.30 this afternoon.

Machinery on the edge had fallen in and was now covered in dirt meters below, he said.

"I was looking out the window and saw it happen," he said.

"It was going like slow motion. I saw the bank starting to give away where the machinery was and the guys starting to scatter and run."

One machine fell on its side and workers managed to pull it back as the edge of the bank gave way, Tucker said.

"Some of the machines are now down in the bottom of the crater.

"It's all under the dirt."

In October, former North Shore and Birkenhead councillor Graham Milne said the former North Shore City Council knew for years about the unstable nature of the land.

"The land has been moving for some time ... it could easily have been prevented by proper engineering right from the start," said Milne, who believed the slip will require substantial work further down the valley towards the Chelsea Sugar Factory.

In 2010, Auckland Council refused to lease Rawene Reserve to the Great Chelsea Gardens Trust, which Milne chairs. One reason given was the unstable nature of the land.

Milne wanted to turn the reserve and 6700sq m of bush he owns adjoining the reserve into a series of ornamental gardens, as well as provide public access from the Birkenhead shopping centre to the Chelsea Sugar Works.

An Auckland Transport spokesman said in October that independent geotechnical experts are continuing to retrieve samples from the site for analysis and a drone is conducting flights every two days to detect any movement.