The wild corner of China, home to most of the world's giant pandas suffered serious damage in last month's earthquake, state media reported.

At least eight per cent of the endangered bear's habitat was completely destroyed and experts have still not been able to assess casualties, the official Xinhua news agency said.

Only 1,590 pandas still live in the wild, all in China, and about 1,400 were in the part of the southwestern province of Sichuan that was rocked by the May 12 earthquake.

"The dense forests covering these places have now turned into bare land," Yan Xun, a State Forestry Administration Official, was quoted as saying. "Landslides and forestry destruction pose severe threats to the lives of the surviving pandas."

The caves and tree hollows where pandas live may have collapsed, torn-up land likely polluted some of their drinking water and paths to their food sources may have been blocked, Xinhua said.

"It is still too dangerous for our staff to go into the field. When conditions allow, we will search the area and see if there are injured pandas that need help," Mr Yan said.

The earthquake also devastated Sichuan's Wolong research centre, the world's most important panda reserve, killing one panda with another still missing.