The Move Forward Party (MFP) needs to make it official that its leader Pita Limjaroenrat intends to waive the party's right to take the opposition leader post, according to House Speaker Wan Muhamad Noor Matha.
His remark came after Mr Pita made it known verbally that neither he nor the MFP wanted the opposition leader's position.
The MFP would rather keep its MP for Phitsanulok Padipat Suntiphada in the role of deputy House speaker.
Mr Wan said the right to assume the opposition leader seat must go to the leader of the biggest part of the opposition. But if they are not able or willing to perform the role, the right is passed on to the next biggest party.
A party cannot have its MP concurrently occupy the positions of deputy House speaker and opposition leader.
The MFP has chosen to retain the deputy House speaker, apparently to push its legislative agenda, and so it must officially notify him of its decision to let go of the opportunity to serve as opposition leader, Mr Wan said.
This is so that the right to take on the opposition leadership may be handed to the second-biggest opposition party, which is the Democrat Party.
"The charter and the parliamentary rules dictate that an opposition leader must be appointed," he said, explaining that the leader of the opposition takes part in selecting members of some independent agencies.
However, the Democrats are struggling to convene a meeting to elect its leader due to deep-seated internal divisions.
If the party fails to produce a full-time leader soon, the right to lead the opposition will be offered to smaller parties, including those with one MP, such as the Fair Party.
But Mr Wan insisted no deadline is imposed on when the opposition leader must take office.
A political source noted the MFP might eventually end up empty-handed as Mr Padipat may risk being stripped of his deputy House speaker post over his alleged online promotion of craft beer, an offence carrying a severe punishment as a political post holder, in Phitsanulok. Mr Padipat denies the allegation.
Also on Monday, Mr Wan said he stands ready to set a date for a parliament meeting where the new cabinet will unveil its policies once he receives word about the cabinet seats being finalised and the timing of the meeting discussed among the government, opposition and Senate whips.