The United Nations and its aid agencies had so far managed to raise only about $182 million, she said.
Hundreds of thousands have been killed in the conflict when ethnic minority rebels took up arms against President Omar al-Bashir's Arab-dominated government in Khartoum, accusing it of economically and politically marginalising the region.
Global donors have been providing funds to meet humanitarian needs of Sudan, with about $11 billion contributed since 2003, including $570 million in 2016.
A UN official on Monday called on donors to provide more assistance to Sudan after the world body received only a fraction of the $804 million it needs for humanitarian aid.
Marta Ruedas, the UN resident humanitarian coordinator, told a news conference in Khartoum that only 23 per cent of the humanitarian aid for Sudan in 2017 had been raised.
The United Nations and its aid agencies had so far managed to raise only about $182 million, she said.
"We look forward to the continued generosity of donors to ensure that critical needs can be addressed in a timely manner," Ruedas said at the news conference to mark World Humanitarian Day.
Since the start of the year, some 2.5 million people have received humanitarian aid in Sudan, she said.
While the nature of assistance cannot be changed on the back of falling donor contributions, some adjustments will have to be made in the targeted number of people needing assistance, Ruedas said.
"It is difficult to prioritise given the limited resources," she added.
Hundreds of thousands of Sudanese still live in camps since being displaced from their homes after a brutal conflict erupted in the western region of Darfur in 2003.
Hundreds of thousands have been killed in the conflict when ethnic minority rebels took up arms against President Omar al-Bashir's Arab-dominated government in Khartoum, accusing it of economically and politically marginalising the region.
Global donors have been providing funds to meet humanitarian needs of Sudan, with about $11 billion contributed since 2003, including $570 million in 2016.
Although the violence in Darfur has been reduced and new displacements fallen significantly, the overall situation remains complicated with hundreds of thousands of South Sudanese refugees crossing into Sudan following a deadly civil war and famine in their country.
Some 416,000 South Sudanese have taken refuge in Sudan since December 2013 when a civil war erupted in South Sudan, less than three years after it separated from the north in 2011.
