The Thai Rice Exporters Association blamed drought, fluctuation in currency exchange and stronger competition from India, Vietnam, China and Myanmar for the drop in volumes.
The association's forecast is the same as that of the Commerce Ministry, which also cited the drought that hit the central, northern and northeastern farming regions, and tougher competition as the factors to reduce export.
The 2020 target would result in the country's lowest export since 2013, when Thailand exported 6.6 million tonnes of rice.
"There is a chance that we may fall to third place this year, with Vietnam overtaking us," said Chookiat Ophaswongse, honorary president of the exporters association.
"Vietnam has no problem with their production cost, as our production will be reduced due to the drought and their price is more competitive," Ophaswongse said, calling the 2020 forecast a "challenging target".
A strong baht, Asia's strongest-performing currency last year, has kept the price of Thai rice higher than the country's competitors, resulting in exports dropping 32.5% to 7.8 million tonnes in 2019 from a year earlier.
The exporters association urged the government to help develop a new strand of rice to expand markets and warned of competition from exporters including China, previously an export market for Thai rice, and Myanmar whose production capability has improved at a lower cost.
"China will become a much stronger competitor due to their production capability and large rice stock," said Charoen Laothamatas, president of the association.
Despite the bleak outlook, the association expects demand for fragrant rice from markets such as Hong Kong, Singapore and China to improve in the near term due to the coronavirus outbreak.
"The spread of the coronavirus has created quite a panic in places like Hong Kong and Singapore which has increased their demand for rice," Chookiat said.
(Reporting by Panu Wongcha-um; Editing by Himani Sarkar and Amy Caren Daniel)
