Adding to the danger was the growth of rich cities along the river, such as Chongqing, Wuhan and Nanjing, making any floods potentially more disastrous.

"Be on the alert that it is likely that a relatively big flood will hit the Yangtze River," the China News Service quoted Cai Qihua, vice-commander-in-chief of the Yangtze River Flood Control Headquarters, as saying.

"Meteorological and hydrological" features within the Yangtze basin this year were similar to those of 1998, Cai said.

The floods that summer left 14 million homeless and caused $24 billion in economic damage.

Cai also said some banks along sections of the Jingjiang River, a section of the Yangtze, could be at risk of collapse.