The UN High Commissioner for Refugees (UNHCR) said on Thursday that according to initial reports the Aro Sharow camp was attacked by 250-300 armed men late on Wednesday.
Another 10 people were reported to have been seriously wounded and the nearby village of Gosmeina was also reportedly attacked and burned, the agency said.
The death toll referred only to camp dwellers.
"The UNHCR is gravely concerned," it said in a statement, adding that it was the first time a camp had been attacked since conflict erupted in the vast Sudanese region over two years ago.
Between 4000 and 5000 people were believed to be living in the camp and most of them fled into the surrounding countryside which the UN considers unsafe, the agency added.
The camp lies 16km north of the town of Saleah in an area that has been regarded as a no-go zone for the UN for months because of continuing violence.
"As long as this insecurity continues, the international community cannot provide the assistance that is so desperately needed by hundreds of thousands of people"
The attackers had apparently burned about 80 makeshift shelters, around a quarter of the camp's households.
The UN's chief of humanitarian operations Jan Egeland warned on Wednesday that violence was increasing in Darfur after a lull and that the UN could be forced to suspend its aid operations there.
Nevertheless, this was the first time that a camp had been attacked since fighting broke out in the vast Sudanese region over two years ago forcing hundreds of thousands to flee to the makeshift settlements, the UNHCR said.
Following the attack, High Commissioner for Refugees Antonio Guterres said it was the responsibility of the Sudanese government to restore order.
More than two million people are
living in the camps
"As long as this insecurity continues, the international community cannot provide the assistance that is so desperately needed by hundreds of thousands of people," Guterres said.
"The government of Sudan has a responsibility to ensure security for all its citizens," he added.
Tens of thousands have been killed and more than two million people are living in the camps, mostly inside Darfur, which is the size of France.
Clashes have continued despite a ceasefire agreement and liltle progress has been made in peace talks in Abuja, the Nigerian capital, brokered by the African Union.