"More rains are expected in the coming days and the estimated number of affected people is likely to rise further," Xinhua quoted the UN Office for the Coordination of Humanitarian Affairs (OCHA) as saying.
At least 26,000 houses have been damaged or destroyed by the torrential rains that began earlier this month, OCHA said, noting initial estimates of the damage in the eight affected states.
Reports said that dozens of people have lost their lives across Sudan.
The UN and its partners have provided a range of emergency relief items, including tents, plastic sheets, blankets, water cans, buckets and mosquito nets from its emergency stockpile in Khartoum state. They also provided mobile clinics, drinking water and sanitation services.
"Other emergency supports are currently being mobilized, particularly food, shelter, water, sanitation, hygiene and health services," OCHA said.
More than 150,000 people have already been affected by the flooding, according to the Sudanese Red Crescent Society, the Khartoum State Commission for Voluntary and Humanitarian Work, the government's Humanitarian Aid Commission and the International Organisation for Migration (IOM).