Watch: Cliff collapse leaves deck hanging precariously

A cliff collapse in Auckland's Eastern Beach has left one property owner's deck hanging precariously over the edge.

Realtor Ben Dellabarca and his flatmate were walking beneath the cliff around noon on Sunday when he saw rocks falling down the cliff, below multimillion-dollar properties on Clovelly Rd.

He said he saw dirt, rocks and even what appeared to be a retaining wall suddenly collapse on to the beach below, narrowly missing the pair's dogs.

"I saw rocks falling, so I called the dogs away, and then the rocks increased very quickly and the whole thing fell away," Dellabarca said.

A house is threatened by a cliff collapse at Eastern Beach in East Auckland. Photo / Ben Dellabarca

He estimated the cliff to be between 10-15m tall, capturing the collapse on video.

Auckland Council geotechnical engineer Ross Roberts said the council had not been alerted to the slip, but would investigate further on Monday morning.

"We have not been alerted to this slip, but this is an area of known instability," he said.

The cliffs on the peninsula are prone to erosion and instability. Then-Mayor of Manukau City, Sir Barry Curtis, suffered the collapse of his Clovelly Rd house in 2009.