Global food prices rose to a record in December, the UN's Food and Agriculture Organization reported Wednesday, surpassing highs in 2008 when rising prices sparked riots in 61 countries.

The FAO food price index — which measures monthly price changes in a basket of foods including cereals, oilseeds, dairy, meat and sugar — averaged 215 in December, up for the sixth straight month, and its highest in nominal terms since 1990.

A woman carries sugar from a government subsidized market as police stand guard in La Paz, Bolivia, in December. Bolivia's decision to reduce fuel subsidies added to rising food prices and sparked unrest until the government rescinded the decision on Monday. (Juan Karita/Associated Press)

That was up from 206.0 points in November and passed the high of 213.5 in June 2008 during the food crisis at that time.

Its sugar price index soared to a record high of 398.4 points from 373.4 points in November.

The FAO's cereals price index, which includes prices of main food staples such as wheat, rice and corn, rose to an average of 237.6 points in December, the highest level since August 2008 and up from 223.3 points in November.

The oils price index rose to 263.0 points in December from 243.3 points in November.

Recent flooding in Australia has disrupted shipments of wheat and sugar, but grain production has also been harmed by drought last year in Russia and heavy rain that affected planting in Canada.

From June to December 2010, wheat, rice, maize and soybeans prices gained by double-digit percentages, with wheat up 69 per cent and maize higher by 53 per cent.

At the same time, demand from emerging economies has been growing.

One difference today compared with the time of food rioting three years ago is the price of oil.

That peaked at $145 US in July 2008, and contributed to increased costs of transporting food.

Crude oil traded Wednesday above $90 but has been rising in price, and forecasters are suggesting it could hit $100.