Dam breach at China's second-largest freshwater lake

About 5700 residents have been relocated after waters breached a dyke at China's second-largest freshwater lake in the south of the country as rescue workers rush to contain further damage from outflows, Chinese state media says.

More than 2300 rescue personnel were working to build a second line of defence for floodwaters after Friday's breach across a 226-metre area in Hunan province, China Central Television reported on Saturday.

No one had been harmed as of early Saturday, reports said.

Footage from state media showed a wave of water surging through a breach in the dyke past several overturned lorries into pools engulfing several houses.

Heavy rainfall pounded parts Hunan province earlier this week, causing the Miluo River in Pingjiang county to swell to its highest in 70 years.

Local authorities responded by activating the maximum emergency response level.

State media showed large parts of towns waterlogged and stranded people being rescued on boats.

Water levels at Poyang Lake in Jiangxi province were also being closely watched, China's Ministry of Water Resource said on Tuesday.