An eccentric Beijing resident has built a huge house among what looks like a pile of rocks dotted with trees on top of a 26-storey apartment block in the capital, reports said Monday.

Neighbours have complained about China's latest architectural oddity, which covers more than 1,000 square metres (10,000 square feet), saying they fear it could cause the structure to collapse on top of them, the Beijing Morning Post reported.

The rocks, said to be imitation shells rather than solid stone, have trees and bushes growing among them, as in classical Chinese landscape painting.

Poking out from between them, sections of the house underneath can be seen -- a blue-framed window here, a balcony under a curved roof there.

At least two neighbours have moved out because of the construction work, which has been going on for years, the paper said.

Others complained about damage to pipes and walls in their units, it said.

"We feel this is extremely unsafe. What if the top collapses in rain and wind storms? What if our ceiling collapses?" the paper cited an unnamed 26th floor resident as saying.

Authorities have posted notices that the villa in the Haidian area in the west of the city is illegal, it added.

Houses standing on top of multi-storey buildings are not unknown in China, where a rising property market is making land more and more expensive.

A developer in central China built 25 luxury villas on top of a shopping mall, which became migrant workers' residences after authorities declared them illegal, Chinese media reported earlier this month.

The fate of the rockery building remains unclear, and law enforcement is often applied selectively in China.

Land disputes have become more frequent as officials and developers seek to cash in on the property boom, so that the government has reportedly forbidden housing demolitions without the owners' consent.