China -- After 11 hours of continuous rain in the Longhui County of central China's Hunan Province, civilians and military relief workers began cleaning up and rebuilding areas most damaged by the storm, China Central Television (CCTV) reported.

Villagers, soldiers and government workers joined forces to remove debris, repair bridges, roads and sanitise areas posing risks to human health, CCTV said.

Flash flooding caused by torrential rain in south China's Hunan province killed 18 people and left 18 missing, the official Xinhua News Agency said on Monday.

Some 25 centimetres (10 inches) of rain fell on Sunday on Longhui county, prompting floods and mudslides that toppled at least 15 houses, Xinhua said.

In South China's Guizhou Province, heavy rain caused heavy flooding and closed roads.

When the storm passed, people gathered to remove mud from houses and restore water and electricity supplies, CCTV reported.

Strong wind swept through Chenzhou County in Hunan Province, toppling trees, damaging buildings and phone and power lines.

Villagers said strong winds hit their county but passed through the area in 30 minutes, leaving a path of destruction but causing no deaths or injuries.

While the months of June through August mark the annual rainy season that sets off floods and landslides in China, storms this year arrived unusually early.

Prior to Sunday, rain storms in southern China, including Hunan, had killed 170 people since late May and forced 1.6 (m) million people to flee their homes.