Sak said the committee had full authority to call for evidence and witnesses from concerned parties and file corruption charges against suspects.

If suspects refuse to produce evidence, they lose the right to protect themselves and have to fight the charges in court.

"If he [Thaksin] returns, it is the duty of the government and Council for National Security to handle him. I have no idea how they will manage [that]," Sak said.

Committee secretary Kaewsan Atibodhi also said Thaksin's return to Thailand would not affect the commission's work.

"We have the anti-corruption law, which empowers us to summon information from concerned parties," he said.

Sak said the draft directives of the commission would be ready for approval soon after the commission secretary's office had thoroughly reviewed the draft.

The commission is investigating eight cases where it believes government corruption was committed.

The eight cases are: alleged tax evasion in the sale of Shin Corp, Exim Bank loan extensions, the Central Laboratory's procurement of equipment, a rubber sampling project, the procurement of fire-fighting equipment, the procurement of bomb detection equipment, an electricity project at Suvarnabhumi Airport, and a mass transit system linking the city and the airport.