Legal experts are questioning whether a parliament rejecting the renomination of Move Forward Party (MFP) leader Pita Limjaroenrat for prime minister was constitutional.

Borwornsak Uwanno, former chair of a constitution drafting committee, on Thursday slammed the resolution on Facebook, saying the Constitutional Court should look into the issue.

"Invoking a parliamentary session regulation has crippled the constitution despite the fact the charter specifically covers the prime ministerial election," he wrote. "It's a pity for Thailand."

He said he was disappointed with MPs who voted against Mr Pita's renomination.

He noted that the parliament's interpretation was not final. Anyone who thought their rights were affected over this matter could petition the Ombudsman.

The Ombudsman will submit the petition to the Constitutional Court, Mr Borwornsak said, adding the affected person can also directly petition the court if the Ombudsman doesn't.

His comments came after a majority of MPs and senators voted on Wednesday to reject Mr Pita's renomination on the grounds that parliamentary meeting regulation No.41 prohibited the resubmission of a failed motion during the same parliamentary session.

Legal scholar Jade Donavanik said that he believed Mr Pita's nomination on July 13 was not a motion, so the regulation should not have been applied.