Vietnam, the world’s second-largest rice exporter, has accumulated 45 percent of a targeted 1 million ton stockpile in a bid to prevent local prices from slumping at harvest time, the Vietnam Food Association said.

Domestic rice prices have been supported by the initiative, as well as by expectations that the Philippines will sign import contracts, Huynh Minh Hue city, general-secretary of the association, wrote in an e-mail to Bloomberg News on Thursday.

The stockpiling program is meant to support prices as the Mekong Delta’s winter-spring rice harvest peaks, Hue wrote. This year’s winter-spring crop may total 10.3 million tons compared with the previous crop’s 10.2 million, he wrote. The group represents cooking producers and traders.

The association announced the stockpile plan, due to run from March 1 to April 15, in a February 11 statement from Chairman Truong Thanh Phong. “The stockpile will reach 1 million tons as scheduled,” Hue wrote in an earlier e-mail to Bloomberg.

Vietnam’s minimum export price for 5 percent broken rice was raised to $490 per ton from $480, the association said in a website statement on March 21. The minimum export price for 25 percent broken rice was raised to $470 from $460, it said.

Vietnam, which competes with biggest shipper Thailand in the global rice market, has targeted exports of about 6 million tons this year, Deputy Agriculture Minister Diep Kinh said in January. That compares with 2010 exports of 6.75 million tons, according to data from the association.

The Philippines, Vietnam’s biggest rice buyer, had agreed to purchase 200,000 tons from Vietnam, National Food Authority Administrator Angelito Banayo said in Manila on Wednesday. Vietnam shipped 1.48 million tons to the Philippines in 2010, according to preliminary figures from the General Statistics Office.