Campaign for Popular Democracy secretary-general Suriyasai Katasila called on the government to reveal the financial routes behind the alleged move.

"If the government does not reveal the evidence, the old power groups can claim that they are the victims of political harassment. The government will lose public support as a result," he said.

Thai Rak Thai Party caretaker leader Chaturon Chaisang accused the Anti-Money Laundering Office (Amlo) of being a tool of the government by releasing a claim that former Thai Rak Thai MPs in northern and northeastern provinces each received Bt3 million to carry out activities to bring down the government.

"We have never had policies to topple the Council for National Security through such methods. We want to be in power through election only. We also will not join with anyone who seized power through staging a coup," he said.

Thai Rak Thai spokesman Kuthep Saikrachang said the allegation about financial support was groundless. "It is a political move to discredit that was made without moral integrity," he said.

Justice Minister Charnchai Likitjitta denied that Amlo had checked the financial transactions of politicians and leaked the reports. He had checked with Amlo secretary-general Pol Colonel Yuthabul Dissaman, who denied the allegation.

Charnchai said Amlo did not have the right to conduct secret examinations of anyone's financial transactions. He said the agency could conduct an investigation only if someone committed offences relating to money laundering.

Paichit Sriworakan, a former Thai Rak Thai MP in Nakhon Panom, said he and other former MPs from the same province had filed complaints with police against Amlo for defamation.