Thailand's government has acknowledged losing more than $4.46 billion in a much-criticized scheme to support rice prices that ended up dislodging the country from its top spot as the grain's exporter.

Prime Minister's Office Minister Warathep Rattanakorn said Tuesday the government's sales of the rice failed to cover the sum it paid to farmers under the 2011-2012 subsidy program.

Under the scheme, the government buys rice from farmers at about 15,000 baht ($490) a ton, hundreds more than the market price. Its inability to resell much of it on the international market allowed India and Vietnam to surpass Thailand in export value .

The government was criticized for refusing to disclose the losses and the amount of stockpiled rice. Prime Minister Yingluck Shinawatra said Thai farmers gained from the program.