Firebrand activist Srisuwan Janya will next week lodge a petition with the National Anti-Corruption Commission (NACC) against the MPs and senators who voted in favour of the charter amendment bill.
A total of 206 MPs and two senators voted for the bill during its third and final reading on Wednesday night but it was not enough for the draft to be passed.
Mr Srisuwan wrote on his Facebook page that he will file the petition with the anti-graft agency on Monday against the 208 lawmakers for alleged ethical misconduct.
He said the group of MPs and senators voted in favour of the bill despite a Constitutional Court decision that a national referendum must first be held to determine if the public wants an entirely new charter.
"So having acted in defiance of the court's ruling, they must face the consequences," said Mr Srisuwan, the secretary-general of the Association for the Protection of the Thai Constitution.
Under the revised NACC law, the anti-graft agency is authorised to submit cases of serious ethical misconduct to the Supreme Court for a ruling.
Mr Srisuwan had threatened to ask the NACC to take action against parliamentarians who voted for the charter amendment bill. He insisted that the court ruling was clear and there was no need for further interpretation.
However, Pheu Thai deputy leader Anusorn Iamsa-ard yesterday shrugged off Mr Srisuwan's planned petition and threatened to file a counter lawsuit against the activist.
He said such a petition has no grounds and that the activist might have a hidden agenda.
Deputy Prime Minister Wissanu Krea-ngam said the coalition government is discussing options including if a national referendum should be held or if it would seek to amend the constitution section by section.
He also rejected calls from the opposition for the prime minister and himself to take responsibility for the aborted charter amendment draft.
Chartthaipattana party-list MP Nikorn Chamnong said the party is prepared to proceed with amending Section 256, which says a charter amendment requires the support of at least one-third of all 250 senators, or 84.
He said the party has agreed that three-fifths of members of the Senate and House of Representatives is needed to endorse charter amendments in the first and third readings.
"Only two senators voted for the bill, so it never saw daylight. This shows that 84 votes of the Senate can wrestle with 500 MPs and that doesn't seem right," said Mr Nikorn.
Parliament president Chuan Leekpai said yesterday an extraordinary session is likely to convene next month to debate the proposed national referendum bill.
The bill was debated on Thursday, but the joint sitting of MPs and senators were unable to conclude on certain issues when the session was adjourned.
In other news, the opposition yesterday petitioned the NACC to investigate Transport Minister Saksayam Chidchob and Deputy Interior Minister Nipon Boonyamanee.
The move followed the recent censure debate in which both ministers were accused of malfeasance and irregularities over land acquisitions related to their family members.