Chief government whip and Palang Pracharath Party (PPRP) MP, Wirach Ratanasate, said key government figures agreed on Wednesday to leave sections 1 and 2 of the charter -- which contain general principles and royal provisions -- unchanged.
The meeting also approved a proposal to set up a charter drafting assembly, Mr Wirach said, adding that government whips will determine the structure of the constitution drafting body, with input from experts at King Prajadhipok's Institute and the Council of State, the government's legal advisory body.
The decision came amid a string of anti-government rallies, which saw protesters pressing for a charter rewrite and reform of the monarchy.
Separately, Deputy Prime Minister Prawit Wongsuwon said he disagrees with the Move Forward Party's (MFP) proposal to amend the constitution's general principles, as well as provisions associated with the monarchy.
Gen Prawit, also the leader of the ruling Palang Pracharath Party (PPRP), called the issue a "delicate matter" as it relates to the monarchy, adding the PPRP was in the process of discussing its charter amendment proposals.
The MFP has made it clear that it will continue to push for amendments to Section 1 and Section 2 of the constitution.
Section 1 of the constitution defines Thailand as a single, indivisible kingdom; a democratic regime with the King as the head of state. Section 2, meanwhile, deals with royal prerogatives.
When asked about changes to sections which give junta-appointed senators' the power to vote in a prime minister, Gen Prawit said the issue is still being discussed.
MFP lawmaker Natthawut Buaprathum said on Wednesday the party supports the opposition-sponsored motion to amend Section 256 of the constitution to pave the way for a charter drafting body to be formed, even though the MFP did not formally sign up for the motion because it disagrees with the other opposition parties' decision to leave sections 1 and 2 untouched.
He also said the MFP will file another motion to amend sections 269 and 272.
Section 269 enabled the now-defunct National Council of Peace and Order to appoint 250 senators to the transitional Senate, for a five-year term. Section 272 allows these senators to join MPs in voting for a prime minister.
Sukit Atthopakorn, adviser to House Speaker Chuan Leekpai, said on Wednesday that Mr Chuan has put the opposition's charter rewrite motion up for debate on Aug 28.