Flood-hit areas of central and southern China braced for more heavy rains Monday with several major rivers already swollen after downpours that have affected millions and left scores dead or missing.

Water Resources Minister Chen Lei warned that at least 10 major rivers in the affected areas were threatening to burst their banks.

"Severe floods triggered by heavy rains will continue to threaten parts of southern China," he said Sunday in remarks posted on his ministry's website.

"There is an increasing possibility that downpours, with enhanced frequency and intensity, will continue to lash regions in the south."

Persistent rains since early June have swamped many areas across a wide swathe of China and the state weather bureau on Monday forecast continued downpours over the next three days, with the summer typhoon season approaching.

More than 1.6 million people in 13 provinces, regions and municipalities had been evacuated from their homes from June 3-20 due to flooding, the civil affairs ministry said Monday.

The rains had left at least 261 people dead or missing while more than 36 million have been "affected" one way or another by the rain and flooding, it added.

A three-hour downpour dumped a near-record 312 millimetres (12.5 inches) of rain in Wangmo county in Guizhou province in the southwest, while over 200 millimetres of rain had fallen over short periods in other regions, Chen said.

State television broadcast footage of the flooded streets of Wuhan, the capital of Hubei province in the centre of the country.

Newspapers carried photos of crowded boats evacuating stranded villagers and numerous flooded roads. In the east of the country, a 30-metre-deep sinkhole slashed into a highway.

Authorities have evacuated 292,000 people from along the Qiantang river in Zhejiang province on the east coast after heavy rains caused the river to swell dangerously, official Xinhua news agency said.

Dykes stretching more than 70 kilometres (40 miles) along the Lan river in the Zhejiang city of Lanxi were at risk of bursting and authorities were preparing evacuation plans for residents in the area, the agency added.

Heavy rains since Saturday have caused the river's water levels to rise sharply, with the Lan reaching its highest mark since 1966, it said.

The Lan was already overflowing at some points while other dyke sections were barely holding.

Authorities have put direct economic losses in Zhejiang province alone at 7.69 billion yuan ($1.19 billion) -- and fruit and vegetable prices have soared by as much as 40 percent after the heavy rains destroyed crops, Xinhua said.

The storms have come as a jarring change for provinces including Hubei, Anhui, and Zhejiang, parts of which had until recently sweltered under the worst drought in decades.

Several days of torrential rain in the southwestern province of Sichuan left nine people dead and 27 missing by Sunday, the country's weather forecaster said on its news website Monday.

In Yunnan, also in the southwest, five people were killed and another was missing after surging floodwaters swept through a pair of rural villages during a hailstorm on Sunday, Xinhua said.

And in the far-western Xinjiang region, four people were reported missing in flash floods that struck on Sunday, the news agency added.

China is hit by heavy summer rainfalls every year.

Torrential downpours across large swathes of the country last year triggered the nation's worst flooding in a decade, leaving more than 4,300 people dead or missing in floods, landslides and other rain-related disasters.

One devastating mudslide in the northwestern province of Gansu killed 1,500 people last August.