The parliamentary debate on cabinet's failure to recite the complete oath during its swearing-in could be held behind closed doors if the content is considered inappropriate to be made public, Deputy Prime Minister Wissanu Krea-ngam said on Friday.
He said parliamentary regulations allowed closed-door sessions for discussion of matters that should remain classified.
"Cabinet ministers or MPs can seek a closed-door debate, which could cover the whole debate from start to end, or begin after a debate has proceeded for a while," Mr Wissanu said at Government House.
He said it was unnecessary that the general debate on the cabinet's swearing-in be closed-door from the start.
"That would be too early, because no one knows what the questions and answers will be at the beginning," Mr Wissanu said.
He also said he had no idea if the prime minister would answer all questions during the debate himself, because the opposition targeted the motion at the whole cabinet.
Mr Wissanu said a date for the general debate had not been scheduled yet.
Opposition chief whip Suthin Khlangsaeng, of the Pheu Thai Party, said the debate should not be behind closed doors without a sound reason, because it concerned a matter that was of the public interest.
"Without a good reason, we do not want it to be closed-door. We wish people have the opportunity to acquire information. But if there is a sound reason, we are ready to cooperate," he said.
He thought the debate should last at least two days.
The planned general debate concerns the cabinet's swearing-in ceremony before His Majesty the King on July 16.
Gen Prayut did not vocalise the last sentence of the oath required by the constitution. Section 161 of the 2017 constitution prescribes: "Before assuming duties, cabinet ministers must swear an oath to His Majesty the King as follows:
"I (name of minister) swear I will be loyal to His Majesty and perform my duties honestly for the benefit of the country and the people. I will also uphold and comply with the constitution of the kingdom in every aspect."
Critics said the incomplete oath could jeopardise the status of the cabinet, its decisions and their implementation.