House Speaker Chuan Leekpai has scheduled the general debate on the cabinet's incomplete oath from 9.30am to midnight on Sept 18, while the opposition said it will target only the prime minister.
Mr Chuan said at the parliament on Wednesday that the cabinet informed him that only Sept 18 would be convenient for the debate - the final day of the current House session.
He could not call a special session and extend the debate for a second day to Sept 19. That would require a royal decree.
Deputy Prime Minister Prawit Wongsuwon said the government was not trying to limit the opposition's debate.
"One day is enough. It is not a sensitive issue," he said.
He did not mind if the debate went behind closed doors or not, but MPs should refrain from any speech that might concern an institution.
Gen Prawit said he expected the oath issue to be concluded in the parliament and not to be raised outside.
Opposition chief whip Suthin Khlangsaeng said they needed 12-13 hours for the debate. There would be 15 opposition speakers
He said they would not raise any sensitive issue that might concern an institution, so the debate should not be closed-door.
He demanded Prime Minister Prayut Chan-o-cha answer questions directly, saying, "That will show responsibility and spirit."
The opposition sought a general debate on 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.
