Any coalition party dissatisfied with being in government should consider stepping down and joining the opposition, said Anusorn Iamsa-ard, a Pheu Thai Party-list MP.
His comment followed remarks on Friday by Deputy Prime Minister and Interior Minister Anutin Charnvirakul, who also leads Bhumjaithai, the second-largest coalition party.
He said he was ready to join the opposition if the Bhumjaithai Party (BJT) is removed from overseeing the Interior Ministry.
Mr Anutin earlier indicated that control over the Interior portfolio was part of the agreement underpinning BJT's participation in the Pheu Thai-led coalition government. However, Mr Anutin said he remains confident he will retain the Interior Ministry post.
Mr Anusorn, responding to the postponement of a mobile cabinet meeting originally scheduled for June 23–24 in Phitsanulok due to Prime Minister Paetongtarn Shinawatra's overseas commitments, on Saturday suggested the delay could be linked to an anticipated cabinet reshuffle. He emphasised that a cabinet reshuffle is the prime minister's prerogative and urged the public to trust her.
"If the cabinet is reshuffled, the government's performance may improve with new ministers and fresh thinking. If not, the current ministers can still carry out their duties," he said.
He added Ms Paetongtarn is not fixated on a cabinet shake-up but is focused on addressing national and global challenges.
"Given today's intense global competition, every minister must operate at full capacity," Mr Anusorn said.
He also urged any incoming ministers to be prepared from day one, warning there would be no "honeymoon period" because the public's suffering cannot wait.
"If coalition parties are unhappy in government and unwilling to embrace the changes necessary to help the administration function more effectively, they can choose to leave and become the opposition. That's part of democratic politics -- whether in government or opposition, you can still serve the country and its people," Mr Anusorn asserted.
Palpee Suwannacheew, a Bhumjaithai MP for Nakhon Ratchasima, criticised Mr Anusorn's comments and questioned his authority to make such suggestions.
"What power does this MP have to tell coalition parties to leave? The authority to reshuffle the cabinet lies with the prime minister.
"The coalition parties are awaiting her decision. But sometimes even the sound of a fly or gnat can be irritating," Mr Polpee said sarcastically. As a constituency MP, Mr Polpee said the public is less concerned with cabinet reshuffles than with economic survival and day-to-day living.
"People are worried about putting food on the table, not about who's in or out of the cabinet. Politicians should focus on addressing these issues instead," he said. He also raised concerns about escalating border tensions.