A report on Monday from the Norwegian Refugee Council's Geneva-based Global IDP Project warned of a major crisis in the area, because aid workers could not reach those displaced due to the fighting and government restrictions on aid workers' movements.
"We are seeing one of the worst crises in Africa unfolding there (in Darfur)," Raymond Johansen, secretary-general of the Norwegian refugee organisation, said.
With some four million forced from their homes by all conflicts within the country, Sudan has the highest number of internally displaced people (IDPs) in the world, the group said.
In February last year, two rebel groups launched a revolt in remote Darfur, accusing the government of neglecting the poor area and arming Arab militias to loot and burn African villages.
"We are seeing one of the worst crises in Africa unfolding there (in Darfur)"
Global IDP Project
The Global IDP Project said there were consistent reports from Darfur of systematic attacks on civilians, burning and looting of villages, large-scale massacres, rapes and abductions.
The United Nations has said the fighting displaced up to a million people in Darfur, a figure the government dismissed as "rubbish".
The project added that despite peace moves in the south of Sudan, people continued to be forcibly displaced in other parts of the country, including the Western Upper Nile region where there are major oil deposits and foreign oil firms operate.
Hundreds of thousands of people were returning to their homes in southern Sudan, and many more were expected to follow if there is a final peace agreement for the region, but local administrations appeared unprepared to cope with the serious challenges of mass return, the Project said.