The UN Food and Agricultural Organization says that world food prices have risen to their highest level in two years.
It says the increase is due partly to a drought in Russia and to government sales restrictions which have brought about a surge in the price of wheat.
The Rome-based agency says that its food price index shot up 5% between July and August.
However, this is 38% down from its peak in June 2008.
The UN says there are sharp differences between the current situation and the spring of 2008, when the price of oil and demand for biofuels pushed world food stocks to their lowest levels since 1982.
The forecast for global rice production in 2010 was also revised downward.
Much of the revision was due to floods in Pakistan and lower expectations in China, Egypt, India, Laos and the Philippines.