The deaths do not include people killed during ongoing violence in Sudan's arid western region, said spokesman Brian Grogan on Monday.
Last week, Egeland said earlier estimates of 70,000 dead from last March to late summer were too low, telling a news conference: "Is it three times that? Is it five times that? I don't know, but it is several times the number of the 70,000 that have died altogether."
Egeland now estimates that an average of 10,000 people have died each month over the past year and a half from malnutrition and disease, Grogan said.
Conflict has raged in Darfur for more than two years with groups fighting the government for power and resources.
Egeland estimates 10,000 people
a month have died
In response, the government says it recruited militias to fight the rebellion but not the Janjawid, which it calls outlaws.
Two million people have fled their homes since early 2003, mostly to camps near towns and some to neighbouring Chad.
The UN Security Council this week expects to adopt a resolution that would authorise a 10,000-member peacekeeping force in southern Sudan to monitor a landmark accord that ended 21 years of civil war.
Council members are at odds over where to try cases of gross human rights violations.
The United States is opposed to the International Criminal Court in The Hague and instead has proposed a new tribunal in Arusha, Tanzania. No other council member supports that proposal.