Deluges in Guizhou -- classified as a southwestern province by the Chinese government -- have prompted authorities to activate the highest-level emergency flood response, evacuating around 80,900 people by Tuesday.

On Thursday state broadcaster CCTV said "exceptionally large floods" had swept through in Guizhou's Rongjiang county since Tuesday.

"As of 11 am on Thursday... six people have unfortunately lost their lives," the report said, citing the local flood control headquarters.

"Many low-lying areas in the county were flooded, and the infrastructure of some towns was seriously damaged, resulting in traffic obstruction, communications blackouts, and some people being trapped," the broadcaster said.

"The water level in the county has now retreated below the warning level," it added, saying "post-disaster recovery and reconstruction and investigation of trapped people are underway".

Xinhua reported Wednesday that a football field in Rongjiang was "submerged under three meters of water", and a resident told the news agency they were rescued from the third floor of their home.

China is enduring a summer of extreme weather.

This week, authorities issued the second-highest heat warning for the capital Beijing on one of its hottest days of the year so far.

And tens of thousands of people were evacuated last week in Hunan province -- neighbouring Guizhou -- due to heavy rain.