The King of Thailand has given his formal approval to a coup in which military leaders ousted Thailand's democratically-elected government.

In a televised ceremony, an army officer read out a royal decree of assent, before coup leader General Sonthi Boonyaratglin knelt before a portrait of King Bhumibol Adulyadej.

There was a small pro-democracy protest in Bangkok earlier today, which passed off without incident.

The new leadership is continuing to ban all political meetings and has assumed legislative duties in the absence of a parliament.

The military is expected to form a nine-person panel to investigate alleged corruption under ousted leader Thaksin Shinawatra.

The panel, modelled on a commission originally set up by the prime minister, is also expected to target Mr Thaksin's political colleagues and relatives.

The auditor-general has already speeded up existing probes, including an investigation into whether Mr Thaksin's family legitimately avoided paying tax on its $1.9 billion sale of the firm he founded.

Mr Thaksin, a former police colonel whose Shin Corp grew into Thailand's biggest telecommunications group, has denied charges of corruption.