The world will see bumper harvests this year, but that might not be enough to protect the world's poorest countries from food bills four times higher than at the start of the decade, the United Nations forecast.

Increased plantings and good weather will provide a global wheat crop 8.7 percent greater than last year, one of the reasons wheat prices have slid some 50 percent since February, the Food and Agriculture Organisation said.

But rice -- a staple for more than half the earth's population -- will remain in short supply on global markets, and poor countries that rely on food imports could see food bills up 40 percent this year after a similar price hike in 2007.

"The sustained rise in imported food expenditures (for poor countries) ... constitutes a very worrying development," FAO said in its Food Outlook report. "Their annual food import basket could cost four times as much as it did in 2000."    

In total, world cereal production is set to rise 3.8 percent, driven by the bumper wheat crop, FAO said.

The United States will produce 16 percent more wheat than last year in its biggest harvest since 1998. The European Union, which suspended 'set-aside' rules that force farmers to leave fields fallow, will enjoy a 13 percent bigger wheat crop.

Continually rising demand, high costs and the need to replenish stocks will prevent prices crashing, FAO said.

"In recent weeks, international prices of many agricultural commodities have started to fall and early indications do not preclude further declines in the coming months, however prices are unlikely to return to the low levels due to a host of reasons," it said in the report.

Rice output is set to rise this year -- by 2.3 percent -- and unlike last year more rice will be produced than is used.

But export bans that several producing countries imposed to protect domestic availability of the staple will mean not enough rice is available on international markets to dent prices that soared 71 percent in the first four months of 2008.

"The pressure would considerably ease if India, which is about to harvest a bumper 2007 secondary crop, would relax its current export curbs," FAO said.

The global spike in food prices in the last year has been put down to a "perfect storm" of factors including increased demand from rapidly developing countries India and China, growth in biofuels production, and the effect of high oil prices on production and distribution costs.

While supermarket prices have risen in richer nations, the effect is much harsher in developing countries where people spend 50-80 percent of their income on food. Consumers have protested and in some cases rioted against price rises.

According to FAO's Food Outlook, the amount of grain used to produce fuel will rise 40 percent this year. Of the total 98 million tonnes used for biofuel, maize will account for 92 million tonnes, 79 million of which will be transformed into ethanol in the United States.

The use of food for fuel, once touted in Europe and North America as an environmentally responsible alternative to fossil fuels, has become increasingly controversial amid soaring world food prices. - Reuters