The dire assessment from UN emergency relief coordinator Jan Egeland came at a deadlock over legal steps that could bring an end to the bloodshed, which has killed tens of thousands.
Egeland, responsible for running UN aid operations across the globe, including for the Asian tsunami, said on Friday that the ongoing violence in Darfur is hampering aid efforts.
He put pressure on UN Security Council nations to put aside differences and take steps to end the bloodshed, which he said was impeding the delivery of food to the starving.
"Too often the world sends us the Band-Aid, and the world believes that we keep people alive and then they don't have to take a political and security action," Egeland told a news briefing.
"This is wrong," he said. "That's why we are really tired of being that kind of a substitute for political and security action."
Egeland (L) wants to take steps
to end bloodshed in Sudan
He said the strife in Darfur risked leaving as many as four million people without access to emergency food relief because of security concerns.
Relief workers are being threatened, attacked and killed in Darfur, where fighting between the government and rebels has sparked disputes over how to deal with potential war crimes.
"We did prevent the massive famine that many predicted, but I think now it's time to say we may perhaps not be able to do so in the coming months if the situation keeps on deteriorating," he said.
UN Secretary-General Kofi Annan this week said the people of Darfur were living through "hell on earth", but the Security Council - largely for political considerations - is divided on what to do.
While it has taken the lead in bringing attention to Darfur, the United States opposes bringing rights violators to the International Criminal Court (ICC) at The Hague because it fears political trials against its own nationals.
"We did prevent the massive famine that many predicted, but I think now it's time to say we may perhaps not be able to do so in the coming months if the situation keeps on deteriorating"
Jan Egeland, UN emergency relief coordinator
Washington has proposed war crimes trials at an ad hoc tribunal in Tanzania, a proposal rejected by Algeria and China - which back Sudan's call for its own domestic trials - as well as other council nations that want ICC trials.
The diplomatic impasse has tightened pressure on the United Nations, amid US criticism that the world body is unable to honestly address grave international crises.
UN officials have insisted that an international commitment in Darfur will end the ongoing violence between the government and rebels who launched an uprising two years ago.
But some Security Council nations have said that the Sudan government needs more time to rein in proxy militias blamed for a scorched-earth campaign of rape and murder that has killed tens of thousands.