The Yellow River, China's second longest river, is likely to flood in its middle and lower reaches this summer, the river's monitor agency said on Tuesday.

The prediction, based on the long-term weather and climate forecast, said that the southern part of North China, the Yellow River region, the Yangtze River region and the Huaihe River region are expected to see more rainfall than in past years.

Henan and Shandong provinces, located in the middle and lower reaches of the Yellow River, will see a rise rainfall this summer by 20 to 50 percent compared with the average level, according to data released by the Yellow River Conservancy Commission of the Ministry of Water Resources.

Chen Xiaojiang, director of the commission, said during a conference on flood-prevention on Tuesday that the Yellow River has not experienced floods of more than 10,000 cubic-meters of water a second.

The last time the Yellow River experienced a flood with more than 10,000 cubic meters a second was in 1982, when it reached 15,300 cubic meters a second.

"Although flooding occurs irregularly, it will be more likely for the rivers to meet in flood if there has not been flooding for a long time," Chen said.

Nearly 1.9 million people live in the lower stream of the Yellow River. The flood may pose grave threats to their safety, said the commission.

Guo Gengmao, governor of Henan province, said during the conference that it is a tough task to rein in the Yellow River and the river's safety is closely related to the grain yield, the hydropower plants and the ecological development in the region.

The flood-distribution projects in the lower stream of the Yellow River have not been completed and the infrastructure construction along the river remains in a poor condition, adding to the threats of possible flooding, Guo said.