The floods have left 273 dead and 218 missing since July 1, Al Jazeera's Melissa Chan, reporting down river from the Three Gorges Dam in Hubei province, said. The direct economic losses are estimated to be around $20bn, she said.
More than eight million people have been forced to leave their homes since the floods began.
Among the worst-hit provinces are Guangxi and Guangdong, affecting the lives of more than one million people.
In Shaanxi province, more than 200,000 residents have been evacuated from their homes.
State media reported on Saturday that Shaanxi's Luofu river, which feeds into the Yellow river, burst its banks near the city of Huayin.
Wen Jiabao, China's prime minister, also issued a warning of worse rains to come while on an inspection tour in Hubei.
He urged local authorities across the country to brace for "more serious floods and disasters," saying that the situation was at a "crucial stage," Xinhua news agency reported
Three Gorges 'critical'
Huge amounts of water thundered out of Three Gorges' massive spill-gates on Friday as authorities in Jiangxi said the eastern province downstream was at a "critical juncture" in flood control.
The provincial government ordered authorities to redouble flood prevention work along dozens of lakes and rivers already swollen by weeks of heavy rains.
"Over the next 20 to 30 days, the high water level of the Yangtze River's Jiujiang section and Poyang Lake will continue. The flood situation is very grim," the provincial government said in a statement.
With a wall running over two kilometres wide and 185 metres tall, Three Gorges was built at a cost of $27bn.
The reservoir behind the dam holds around 39 trillion litres of water, but it is now reaching its limit.
Already authorities have been forced the close the massive shipping locks built into the dam.
Zhao Yunfa, the deputy director of the China Three Gorges Corporation's dispatch centre, said this week that the dam's capacity can only withstand floods that reach up to 83,700 cubic metres per second - only about 18 per cent more than the dam's record water flow on Tuesday, the China Daily newspaper reported.
"The dam's flood control capacity is not unlimited," the newspaper quoted Zhao as saying.
Liu Ning, the vice-minister of water resources, meanwhile, has warned of more misery to come as the typhoon season gets into gear. He said six to eight major typhoons were expected in the coming months.