Chinese authorities rushed Tuesday to evacuate 12,000 people threatened by a dyke breach as the death toll from widespread flooding across the nation's south rose to nearly 200.

China's President Hu Jintao called for all-out rescue efforts in response to the dyke breach in Jiangxi province, as torrential rains that have battered a broad swathe of southern China for 10 days continued.

The civil affairs ministry said the persistent downpours since June 13 and resulting floods and landslides had left 199 people dead and another 123 missing.

Authorities have already evacuated 68,000 people from areas around the Changkai dyke in Jiangxi that collapsed after a swollen river burst its banks, the provincial flood control headquarters said.

But water in a reservoir upstream from the dyke had now exceeded danger levels, further threatening the thousands who had still not moved out of harm's way downstream in Fuzhou city, according to the official Xinhua news agency.

Both Hu and Premier Wen Jiabao ordered intense rescue efforts to battle the flooding and rescue victims of the dyke breach, according to the headquarters, as state television broadcast footage of towns and large swathes of land in the area submerged in brown, muddy water.

The floods, which have hit 10 provinces or regions, have also triggered the evacuation of 2.4 million residents and caused nearly 42 billion yuan (six billion dollars) in estimated economic losses.

The National Meteorological Centre warned Tuesday that parts of southeastern and southwestern China would see persistent heavy rains over the next 24 hours.

In Jiangxi, more than 10,000 soldiers and civilians had been mobilised for rescue and relief work after the dyke collapse, and authorities called for desperately needed tents and food for the displaced, Xinhua said.

But transport of relief material was hampered by the widespread flooding of roads in the area, it added.

State television broadcast images of rescuers in Fuzhou rowing boats through its submerged streets to fetch people stranded in buildings.

Relief workers were also seen throwing ropes to stranded flood victims clinging to submerged trees amid raging torrents and pulling them to safety.

Authorities in Fuzhou have set up 17 makeshift shelters for flood victims at stadiums and local schools, Xinhua said, adding that no casualties had been reported so far.

According to the civil ministry, the torrential rains and flooding have led to the collapse of 195,000 homes and damages to 568,000 others throughout the 10 provinces and regions, while 1.6 million hectares (3.9 million acres) of crop land have also been damaged.

Alternating floods and droughts have plagued China's people for millennia.

Large flood-hit areas of southern and southwestern China, particularly Guizhou, Guangxi and Chongqing, had only just recently emerged from a crippling drought that in some regions was the worst in a century.