Provincial officials have 30 days to complete the inspection of rice stored at 1,800 warehouses nationwide under a deadline set by the National Rice Policy Committee chaired by Prime Minister Prayut Chan-o-cha.
Officials have to figure out the exact amount of good-quality and rotten rice in the 13.5 million tonnes the state has held for several years.
The findings will help the government to decide appropriate prices for sale, commerce permanent secretary Chutima Bunyapraphasara said.
She said some observers believed the auction prices were too low.
Stocks are kept in warehouses in 51 provinces. Estimates are that 4.6 million tonnes are substandard rice and 1.3 million tonnes are rotten.
The 13.5 million tonnes were accumulated from the rice-pledging scheme run by the previous government from 2011-14.
As the scheme paid farmers 15,000 baht a tonne for paddy or up to 24,000 baht a tonne for milled rice, Thai rice lost competitiveness in the global market, resulting in the huge stockpile.
Exporters have estimated significant losses from the rice sales with the low auction prices.
Fourteen bidders recently won bids to buy 246,793 tonnes of rice at 2.34 billion baht from the ministry, meaning bidders pay 9,460 baht a tonne.
Therefore, the state receives less than 10 baht a kilogramme, far lower than the 24-baht production cost of rice excluding expenses for storage and maintenance, said Chookiat Ophaswongse, an honorary president of the Thai Rice Exporters Association.
Although the price of Thai rice is less competitive in the global market, the weak baht is a positive factor that drove exports to 6 million tonnes in the first eight months of this year, drawing high hopes that Thailand can achieve its target of 9 million tonnes this year.