Meanwhile, meteorologists at the National Meteorological center said the rainfall, which has been strong since earlier this month, will lessen in the coming week.
From Monday to Thursday, Northeast China will see light to moderate rain, while eastern parts of Heilongjiang and the Inner Mongolia autonomous region will see heavy rain.
Even so, Heilongjiang, Jilin and Liaoning are gearing up for even worse flooding.
Among the big rivers in Heilongjiang, only the Wusuli River has had its water level below the danger level, said Hou Baijun, deputy director of the provincial flood control and drought relief headquarters.
All other rivers have reported their biggest floods since 1998.
According to the provincial civil affairs department, the disaster has killed 11 people, destroyed 1.44 million hectares of crops, flattened 2,560 houses and affected nearly 2 million residents since Aug 10.
Direct economic losses stood at 7.1 billion yuan ($1.16 billion), the department said.
In nearby Jilin, at least 14 people have died in the disaster. The flood also cut off roads, damaged reservoir, and forced dozens of businesses to suspend production.
In Liaoning, 15 flood-related deaths were reported in Fushun on Sunday, and 32 people disappeared after a torrential rain hit the region on Friday. More than 300,000 people in the city were affected by the disaster.
"The water rose so fast that people couldn't prepare for it," said Chu Yongge, a native of Fushun's Qingyuan county. "At my courtyard, the flood rose to about 2 meters within minutes on Friday night."
Hundreds were stranded on their rooftops for hours before emergency workers moved them to safe areas, he added.
In addition to regional governments that delivered relief supplies, China's central authorities on Saturday sent relief supplies to flood-hit areas in the northeastern region.
The National Commission for Disaster Reduction and the Ministry of Civil Affairs issued a Level IV emergency disaster relief response at 5 pm on Saturday, with a special work team sent to the region to guide local relief efforts.
A total 3,000 tents, 5,000 cotton quilts, 2,000 folding beds and 3,000 sleeping bags were delivered to disaster victims.