BANGKOK (AP) -- The Thai Cabinet has extended a rice-buying scheme that has been plagued by complaints of corruption and threatens the country's long-time reign as the world's top rice exporter.

The Cabinet on Tuesday approved a tentative budget of 240 billion baht ($7.8 billion) to buy 15 million tons of rice at above-market prices from farmers for another year.

Prime Minister Yingluck Shinawatra said the subsidies have raised the incomes of Thai farmers. She vowed to solve corruption in the program.

The scheme, which started last year, is popular in the north and northeastern strongholds of Yingluck's party.

But critics said it had caused a plunge in Thailand's rice exports due to the high price guarantee at home.

Vietnam is expected to surpass Thailand as the world's biggest rice exporter this year.

Copyright 2012 The AP.