In addition, 250,000 people in Dazhou city, Sichuan province, had been made homeless and forced to relocate with a total of two million people affected, the official from the city civil affairs department told AFP.

Some 26,800 rooms in homes had collapsed, said the official who identified herself only by her surname, Zhang. China calculates damage to structures by rooms.

The water level has reached up to the third floor of some buildings, submerging the streets in the city, the Xinhua news agency said.

All roads leading to the city had been cut off following torrential downpours which have dumped 461 millimetres (18 inches) of rain on the city since Wednesday, it said.

Armed police were evacuating residents to safe areas and government officials had rushed to the flood-hit zone, Xinhua cited a local official as saying.

The latest deaths bring the toll from flooding this year in China to about 800 people killed or missing, with the main July-August flood season just starting.

Floods have always been part of life in China but this year they have been more devastating than usual.

The most severely affected areas have been the southern provinces of Zhejiang, Fujian, Jiangxi, Hunan and Guangdong, as well as Guangxi Zhuang region, where unusually heavy rain had caused rivers to swell.