Surayud had earlier promised to hold a referendum on a new constitution in September, followed by legislative polls in December, to restore democracy following last year's military putsch.

"We are looking at the possibility of having an early election, which is a key concern of people outside Thailand," he told reporters.

"We might have a referendum ahead of the target, possibly on August 19, so that the election could be held earlier than planned," he added.

Exactly who will stand in the polls remains unclear after Thai Rak Thai (TRT), the popular party formed by ousted prime minister Thaksin Shinawatra, was dissolved in May over electoral fraud violations.

The military-appointed Constitutional Tribunal also banned 111 senior TRT members from politics for five years, and the junta-backed parliament has not yet passed a new law which would allow members of TRT to register a new political party.