Jan Egeland, the UN relief co-ordinator, said Malawi was in desperate need of $88m (£48m) in aid after suffering its worst harvest for a decade. His claims were backed by the aid agency Oxfam, which said that up to 10 million people in southern Africa could face food shortages after the rains failed.
Ten days after the UN pleaded for funds, Mr Egeland told reporters: "We have received zero pledges for this appeal."
Malawi produced only 1.3 million tons of maize this year, although 2.1 million tons is needed to stave off famine. Oxfam began to distribute food in the hardest-hit areas this week, but says it needs much more.
Several hundred thousand people in neighbouring Zambia, Mozambique, Lesotho, Zimbabwe and Swaziland will also not have enough food over the next six months unless help is provided quickly. The crisis is expected to peak between November and February as food runs out.
HIV/Aids has exacerbated the problem, because many farmers who caught the virus have been unable to work their lands. Southern Africa has some of the world's highest rates of HIV infection, with more than 30 per cent of the adult population believed to be HIV-positive, and aid agencies have said any funding would have to deal with the underlying economic and social causes of famine.
Mr Egeland asked the oil-producing countries to set aside some of the profits they have made from high oil prices to help the areas affected.
He said: "There are many countries in the Gulf and elsewhere who have received an enormous windfall from these oil prices. We can save a life for a $1 a day."