Hom mali fragrant rice production for the 2018-19 main crop is expected to drop 10% from the previous season because of drought in the North and Northeast.
Vice-minister Jintana Chaiyawonnagal said the Commerce Ministry's preliminary survey found that rice plantations in the northern and northeastern areas were hit hard by irregular rainfall.
As a result, paddy production for the annual harvest season, which starts later this month, will decline from 7.6 million tonnes in the previous season.
Last year's premium rice production also fell from 7.9-8 million tonnes of paddy in previous years because of the impact of floods.
The Commerce Ministry in partnership with the Agriculture and Cooperatives Ministry surveyed rice plantations in 16 provinces during August and September.
The two ministries predicted overall rice production will stay at around 25 million tonnes of paddy rice this year, on par with the previous season, boosted by white paddy and glutinous paddy production.
White paddy production is estimated at 9.2 million tonnes, a marginal rise from the previous season, while glutinous paddy production is predicted to rise to 6.2 million tonnes from 6 million.
Kriangsak Tapananon, president of Thai Rice Mills Association, said in upper northeastern provinces like Sri Sa Ket, Mukdahan and Sakon Nakhon, rice production was much better than last year because of regular rainfall in those areas.
But the lower Northeast, including Nakhon Ratchasima, Buri Ram, Surin, Maha Sarakham and Khon Kaen, will likely see production fall from drought.
"If there is no rain within 15 days, hom mali rice production will definitely fall in those 4-5 drought-afflicted provinces," Mr Kriangsak said. "A clearer estimate is expected to become available after October."
According to the Foreign Trade Department's data, in the first nine months, Thailand shipped 8.4 million tonnes, up 2.9% year-on-year, with an export value of US$4.31 billion (141 billion baht), up 21.4%.
Nine-month export volume accounted for 84% of the rice export target set at 11 million tonnes this year by the ministry. Average export price is predicted at $512.67 per tonne, up 18%.
Thailand should export an average of 860,000 tonnes a month for the remaining months to achieve shipments of 11 million tonnes of milled rice as projected, said the department.
The Thai Rice Exporters Association recently raised its export forecast to 11 million tonnes this year, worth $5.6 billion, from 9.5 million tonnes worth $4.3 billion.