Democrat Party leader Abhisit Vejjajiva has repeated his call for a public referendum on a new charter, saying political conflicts could reignite without one.
He said on Sunday the charter will probably be contentious for many people and if it is not put to a vote after it is endorsed by the National Reform Council (NRC), it could spark conflict.
He said dissent over the new charter won't help the reform process and could disrupt the National Council for Peace and Order's (NCPO) roadmap to elections.
The Constitution Drafting Committee has come up with several charter proposals, some of which have drawn fire. One includes a plan for a prime minister who does not have to be an MP. Mr Abhisit has said that would be undemocratic.
Mr Abhisit said public expectations of reform will be high this year after the NRC has completed its charter recommendations. There has been little to no progress made in efforts to reform key areas like energy, education and the economy, he said.
The Democrat leader also said the NCPO and government will face growing pressure, particularly from those who demand freedom of expression and regard martial law as curbing civil liberties.
Mr Abhisit also raised concern that impeachment cases for which the National Legislative Assembly (NLA) will start hearings this week will stoke political conflicts. The NLA will consider impeachment cases against former Senate speaker Nikhom Wairatpanich and ex-House speaker Somsak Kiatsuranon on Thursday, and against ex-premier Yingluck Shinawatra on Friday.
Surapong Tovichakchaikul, a core member of the Pheu Thai Party, said he would file a petition to the NLA to stop its hearings. He said three commissioners of the National Anti-Corruption Commission, which sent the impeachment recommendation to the NLA, were appointed when they were directors of private companies, which may have tainted the process.