The global food crisis is largely responsible for driving up the United Nations' need for funding to confront disasters and emergencies around the world this year by one-fifth, the U.N. said on Wednesday.

World prices of basic foodstuffs such as wheat and rice have doubled over the last year, badly hitting poor nations that rely on food imports and sparking food riots in Africa and elsewhere.

A mid-year review meeting to assess U.N. aid funding needs for 2008 heard that the original appeal for $3.8 billion (1.9 billion pounds) announced in December and quickly revised to $5.4 billion to accommodate extra crises now stood at $6.5 billion.

The cash is needed to meet appeals for food, shelter, clean water and other necessities in 10 countries, mainly in Africa, plus the west African region.

"One of the main reasons for the rises is because of the global food crisis," U.N. humanitarian chief John Holmes told a news conference, although he said natural disasters and conflicts were also to blame.

So far this year donors have contributed $2.9 billion, meaning another $3.6 billion is needed if the revised target is to be met. "The donors will need to dig deep into their pockets to try to find that money," Holmes said.

The biggest focus of the appeal is Sudan, where the 5-year-old conflict in the western Darfur region has driven an estimated 2.5 million people from their homes. The new funding requirement for Sudan is $1.95 billion.

However, the biggest percentage increase is for Somalia, where continued internal fighting has combined with drought to make many more people destitute. The aid requirement there has jumped nearly 60 percent in six months to $641 million.

Other needy countries are the conflict-ridden Democratic Republic of the Congo, now requiring $736 million this year, cyclone-hit Myanmar ($481 million) and Zimbabwe, struck by political, economic and weather-related crises ($394 million).

The biggest supporters of U.N. aid projects have in the past been the United States and the European Union, but Holmes, underlining a point he made at the original launch, stressed the need for new donors, including from the private sector.