DHAKA, BANGLADESH - FARMERS across Bangladesh began their first rice harvest of the year on Thursday, with authorities forecasting a bumper crop which could ease punishing price rises that have triggered food riots.

The impoverished south Asian country - a net rice and wheat importer which has faced acute food shortages - last year produced 30.5 million tonnes of rice, more than half of it during the main Boro season harvest, officials said.

The vital Boro, or cool-dry, harvest will continue for more than a month, and could be even more productive, government officials said.

But, speaking in Dhaka, he renewed an appeal for a global strategy to tackle spiralling worldwide commodity prices, saying the United Nations was probably the best avenue for dealing with the problem.

This total Boro yield should be over 18 million tonnes or close to two-thirds of Bangladesh's total annual rice output, said government agriculture official Shahidul Islam.

Rice prices, which doubled in the past year, have already started slipping nationwide as hoarders, anticipating greater supplies, have started selling their stocks, Food Secretary Mollah Wahiduzzaman said.

'We hope a bumper harvest will cool down the market for months,' Wahiduzzaman said, noting prices had fallen by 60-70 taka (S$1.38) per 40 kilogrammes.

Last Saturday, 10,000 garment workers angry over high food prices and low wages rioted near the Bangladeshi capital Dhaka, smashing cars and buses and vandalising factories, police said.

Farmers this year tilled almost all their land to cultivate rice in hopes of better prices and to meet a shortfall caused by floods last summer and a devastating cyclone in the disaster-prone nation last November.

The agriculture ministry said the twin disasters damaged around two million tonnes of rice and other grains, resulting in a huge price spike that prompted hundreds of thousands of people to queue at government-subsidised outlets.

The government's food minister, A.M.M. Shawkat Ali, said earlier this month that spiralling food prices had created a 'hidden hunger' in the country of 140 million people.

The government has boosted food relief for the poor through free food distribution, food-for-work programmes and subsidised food sales to tackle the situation.

The government has also begun buying rice from farmers to build a 1.5-million-tonne buffer stock to tackle emergencies, up from an estimated current one million tonnes.

'We must build an adequate buffer stock because commodity prices are at all-time highs globally,' Mr Wahiduzzaman added.

'Donors hardly give any food aid these days and sometimes it's impossible even to buy from the international market.'

Bangladesh's government, which has come under public criticism for failing to contain price rises, recently bought half a million tonnes of rice from neighbouring India to cover the losses due to floods and the cyclone.

Private importers have also imported around 1.5 million tonnes of rice and wheat since last July.

Bangladesh has distributed nearly one million tonnes of rice since last July following the shortfalls caused by last year's natural disasters, and has heavily subsidised diesel and fertiliser to help farmer cultivate their land.