Scores of homes perched on a cliff overlooking the Pacific Ocean in LA County have had their electricity shut off amid steadily worsening landslides.

The community of Rancho Palos Verdes - 25 miles (40km) south of downtown Los Angeles - has long grappled with unstable land, but authorities say the problem has worsened in recent months.

Now, utility companies are stepping in, fearing fires and other destruction caused by rapidly shifting land while some residents insist on staying in their multi-million dollar homes.

The decision by power utility company Southern California Edison on Sunday cut electricity to 140 homes in the neighbourhood of Portuguese Bend, with further cuts possible.

“The movement has accelerated dramatically over the last 12 months, where some areas are moving up to 10 inches (25cm) a week,” said city council member David Bradley, according to CNN.

“You can almost see the ground move.”

An additional 105 customers in the city of 42,000 people were notified that they would lose power on Monday.

Last week, a downed powerline sparked a small wildfire in Portuguese Bend.

"The land movement in the Portuguese Bend community has created such a dangerous situation that we have made the very difficult decision to disconnect power indefinitely to prevent that equipment from igniting wildfire," Larry Chung, a spokesman for the power company.

Gas and water has already been disconnected in the upscale neighbourhood.

The 680-acre (276-hectare) landslide has been ongoing for years at a slow pace. But it has accelerated in part due to heavy rainfall in California over the past two years, expert say.

“The acceleration that’s happening currently is beyond what any of us could have foretold, and it demands more response from the state, more response from the federal government,” said Los Angeles County Supervisor Janice Hahn at a news conference on Sunday.

The top county official added that $5m (£3.8m) had been set aside for disaster relief, but more was needed. She called on California Governor Gavin Newsom to personally visit the area and declare a state of emergency.

Authorities have encouraged residents to leave, but evacuations are not currently mandatory.

Los Angeles County Sheriff Robert Luna said that deputies would deploy drones to monitor the area.

Resident Jim Denver told ABC News that he refused to leave, and said Southern California Edison "left us out in the middle of the ocean to swim home".

"They can send all the warnings they want,” another resident, Tom Keefer, told the New York Times. “We’re not leaving.”

The slow-moving landslide is part of a complex of ancient landslides that was re-ignited by the county's expansion of Crenshaw Boulevard in 1956.

It is one of the largest continually active landslides in the US, and has shifted homes by hundreds of feet over the years. The city also spends some $1m each year to fix a major road due to continuous shifting and cracking.