UN Emergency Relief Coordinator Jan Egeland described the news as a breakthrough, promising that the UN's humanitarian operations would be ready to seize the opportunity and help the Sudanese.
In a letter delivered to the UN's Office for the Coordination of Humanitarian Affairs in Geneva, President Omer Hassan Ahmed Al Bashir promised to provide the access to humanitarian workers.
The UN estimates that half of Darfur's population of 6 million has been affected since the conflict among rebel groups, the Sudanese Government and militias began almost a year ago. There have been frequent reports of murders, abductions, looting and burning during attacks on villages in the region.
More than 700,000 Sudanese are thought to be internally displaced by the conflict, while at least 110,000 others have fled across the border to neighbouring Chad.
Mr. Egeland said UN agencies have so far been able to assist only about 15 per cent of the people in need, while another 3 million have remained out of reach.
"The people of Darfur have endured a humanitarian crisis on a massive scale, but the humanitarian community has been largely unable to assist because we have been prevented from delivering adequate aid up to now," he said.
The UN High Commissioner for Refugees (UNHCR) also announced today that it has relocated almost 900 of more than 4,000 Sudanese refugees from a vulnerable Chadian border town to a safer camp 80 kilometres inland.
UNHCR spokesman Kris Janowski said today that three convoys of refugees have been transferred from the town of Tine to a transit centre at Touloum since the weekend.
The refugees are being relocated because their camps along the Chadian-Sudanese border offer little protection against the extreme weather conditions.
Late last month the Sudanese section of Tine, which straddles the border, came under aerial bombardment. Three people were killed in that attack. There have also been repeated cross-border raids by armed militias on the refugees' rudimentary shelters.
Mr. Janowski said UNHCR staff report that most of the refugees are in generally good health despite their precarious conditions.
Another UNHCR team is travelling later this week to the town of Bamina, about 30 kilometres north of Tine, to investigate reports that 2,000 refugees have recently arrived there.