Former senator Ruangkrai Leekijwattana plans to request a court ruling on whether Democrat Party leader Abhisit Vejjajiva has lost his MP status after being stripped of his military rank.
Mr Ruangkrai said the Defence Ministry's ruling to retroactively dismiss Mr Abhisit from military service for draft-dodging took effect from June 2, 1988.
The dismissal was a form of disciplinary action, Mr Ruangkrai said.
In his view Mr Abhisit was therefore not qualified to run for a seat in the House of Representatives, he said.
The former senator plans to ask the Election Commission to get a Constitution Court ruling on Mr Abhisit's MP status.
The government's stripping of Mr Abhisit's army rank is an attempt to derail the censure debate, Democrat MP Ong-art Klampaiboon said yesterday.
He said the Defence Ministry's order to remove Mr Abhisit of his rank and recall his salary was to obstruct the opposition leader from performing his duty in the censure debate by casting doubt on his eligibility as an MP.
The debate is scheduled for Nov 25-27.
Mr Ong-art said the rank-stripping was also a ploy to block Mr Abhisit as the alternative prime minister should Prime Minister Yingluck Shinawatra fail to survive the no-confidence vote.
Mr Abhisit has repeatedly denied using a falsified military personnel registration document to apply for a job as a lecturer at Chulachomklao Royal Military Academy.
The job exempted him from military conscription in 1987.
The Defence Ministry appointed a panel to probe the allegations.
Mr Abhisit said he did not have a chance to tell his side of the story when the committee wrapped up the probe and ruled to strip him of his rank.
Mr Ong-art said Defence Minister ACM Sukumpol Suwanatat received an order from someone with power over the government to try and keep Mr Abhisit out of politics.
ACM Sukumpol should brace for a legal backlash if it could be proven his order to probe Mr Abhisit was an abuse of authority, Mr Ong-art said.
Democrat spokesman Chavanond Intarakomalyasut said Mr Abhisit's lawyer will ask the Administrative Court today to consider if the rank-stripping order contravenes the law or the Defence Ministry regulations.
Mr Abhisit is innocent and the panel's order was clearly a political attack, Mr Chavanond said.
Mr Ruangkrai said the Administrative Court has no jurisdiction to override disciplinary action taken by the military in ordering the stripping of a rank.
Meanwhile, Pheu Thai Party spokesman Prompong Nopparit said party members will be asked to support a petition for the Constitution Court to examine and rule on whether Mr Abhisit is qualified to remain as an MP after his retroactive dismissal from the military service.
The Pheu Thai will also ask the Election Commission to review whether Mr Abhisit was qualified to be the opposition leader and whether he is eligible for the post of prime minister in the no-confidence motion filed against the government.