The opposition will vote against the charter amendments proposed by the government, Democrat Party MP Jurin Laksanavisit has said.
Mr Jurin, the opposition chief whip, said yesterday the opposition would oppose any efforts by the Pheu Thai Party-led government to rewrite the entire 2007 constitution.
He said any changes should be confined to provisions which are seen as problems affecting the majority of people.
The cabinet on Monday approved a draft amendment to Section 291 of the constitution, marking the first step in a controversial rewriting of the charter.
The amendment would create a constitution drafting assembly (CDA) which would come up with proposed amendments to the charter.
Mr Jurin said the government's real purpose in amending the constitution was not to advance democracy or political reform, but to benefit a certain individual.
No one could guarantee the provisions relating to the monarchy and independent agencies would be left untouched.
Mr Jurin said he suspected the government wanted the changes to proceed apace. The amendment appears aimed at making the process of electing members of the CDA and conducting a public referendum quicker than that proposed in the other draft amendments.
Mr Jurin also expressed concern about rumours that efforts were being made to lobby some senators to vote in favour of the proposed changes.
Democrat MP for Nakhon Si Thammarat Thepthai Senpong said he will distribute 100,000 stickers with messages opposing the government's proposed charter amendments nationwide.
Deputy Prime Minister Chalerm Yubamrung insisted the Pheu Thai Party will not play any role in the amendment process.
Mr Chalerm said the people would elect 77 members of the drafting assembly from each province and the other 22 would be appointed by parliament.
"The Pheu Thai Party has no role in the drafting process even with 15 million voters backing the party," he said.
Mr Chalerm is confident the public will welcome the draft because the candidates will be elected by the people themselves and the assembly would listen the people's opinions during the drafting process.
The new draft charter would be put to a referendum, and if the people don't like the draft, it would be dropped, he said.
Parliament, the government whip, and the public would all participate in the Section 291 drafting process.
Mr Chalerm insisted the government was only amending Section 291 and would never amend any law relating to the monarchy.