Several multi-million dollar mansions at a cliffside estate in Hong Kong are at risk of collapse after record rains last week eroded their foundations.

The rains loosened the soil and carved the side of the cliff in the southern district of Tai Tam, an enclave of celebrities and tycoons.

Some residents at Redhill Peninsula evacuated Saturday due to landslides.

Three houses appeared to be at high risk of falling off the cliff, based on photographs.

Hong Kong is vulnerable to floods and landslides because many buildings and roads are built into steep slopes and such hazards have been heightened by climate change.

Authorities found that two basements had been dug into the ground in one of the homes and they suspect that this was done without approval from the Hong Kong Building Authority.

Another property was found to have illegally extended its terrace garden on the cliff. There was also “some breach of the leases and unlawful occupation”, authorities said.

Luxury homes in the neighbourhood can cost up to $23m (£18.3m). A 2,773-square-foot four-bedroom home sold for $11.4m (£9.1m) earlier this year, according to Mansion Global, a digital news site that covers the global real estate market.

Officials are still evaluating the safety of the cliffside estate and residents have been asked to temporarily close their gardens and outdoor swimming pools pending further checks.

“But our primary focus at the present moment is to stabilise the slope to ensure public safety,” said Bernadette Linn, the city’s secretary for development.

The city will “proceed with the necessary enforcement against the relevant breaches” once the slope is stabilised, officials said.

Officials shut down schools and offices last Friday after the downpour turned streets into raging rivers, and flooded subway stations and malls.

The unauthorised structures in multi-million-dollar homes in Hong Kong is a contentious subject, and critics have in the past accused government officials of turning a blind eye to the illegal works by wealthy businessmen.