The UN children's agency -- or UNICEF -- said cases of suspected acute diarrhoea were reported across 12 of the North African country's 18 states during this period.

"Over 16,600 cases of acute watery diarrhoea in the past 10 months alone were reported with 317 deaths, which is a rate double than the alert level," UNICEF said, raising a previous death toll of 279 reported by UN agencies in late May.

The central state of White Nile was the most affected, UNICEF said in a statement, with more than 5,800 reported cases.

"In the White Nile state, with almost 100,000 refugees living mostly in camps, the situation could worsen as the rainy season begins," the statement quoted UNICEF Sudan representative Abdullah Fadil as saying.

"This is deeply worrying."

The other most affected states were East Darfur, North Darfur, South Darfur, South Kordofan and West Kordofan, said UNICEF.

"Children continue to be the hardest hit," Fadil said, adding that immediate help was needed to support them.

Hundreds of people suffer from water-borne diseases every year across Sudan given the lack of access to clean drinking water.

The country's dilapidated health care sector further aggravates the situation, especially in rural areas during the rainy season.