"Our top priority is to ensure food security and hold down domestic prices," he told Reuters. The state grains buyer is buying parboiled rice at $529.72 a tonne, including CIF, in its latest tender.

A senior food ministry official said private suppliers are no longer reliable sources for grain imports following spiraling global food prices. Although it is the world's fourth-biggest rice producer, Bangladesh has emerged as a major importer this year and is desperately looking for dependable sources as once traditional supplier India keeps a ban on grain exports. The government paid a higher cost to import 250,000 tonnes of rice from Vietnam. The price for 200,000 tonnes of 15 percent broken white rice to be supplied by Vinafood 2 is $545 a tonne, including cost and freight, compared with $389 per tonne it paid in August. The government seeks to import 2.2 3.0 million tonnes of grains, including 1.2 million tonnes of rice, in the year to June, up from nearly 550,000 tonnes in the previous year. Analysts say Bangladesh faces unrest if prices continue to rise, given that nearly 40 percent of its population of more than 150 million survive on less than $1 a day.