The guideline price set by the Rice Exporters Association briefly dipped below $500 at the end of May but has jumped since, after the party that won Thailand's general election on July 3 promised a big increase in the price paid to farmers.

Separately, a Commerce Ministry official said Thailand would be willing to renegotiate a deal with Indonesia for 300,000 tonnes that was tentatively agreed in a memorandum of understanding under the old government but never ratified.

"There was a misunderstanding on the rice deal. The MOU was signed as the government was changing," said Manat Soithong, director general of the Department of Foreign Trade.

"We're willing to sell rice to Indonesia but the new government would like to talk on the amount and price."