The abolished 1997 and 2007 charters will not be used as models in the drafting of the next constitution, a member of the Constitution Drafting Committee (CDC) says.
Paiboon Nititawan, a charter writer appointed by the National Reform Council (NRC), said the new constitution will be written "from scratch" to reflect the reforms under way, except for chapters on the constitutional monarchy.
Expected to undergo drastic changes are the election systems involving MPs and senators and the formation of a cabinet, he said.
Mr Paiboon, a former senator, said the powers of political parties should be reduced while the public should be allowed to take a more active role in politics for the reforms to take root.
With this in mind, he proposed the party-list system be abolished to reduce parties' powers.
He also proposed a whole province should be designated as a constituency and the number of MPs in each province vary depending on the number of eligible voters. Candidates who get at least 80% of the vote would win an election.
He insisted political parties are to blame for the conflicts that have troubled the nation for years.
"Based on my proposal, those who stand to lose are political parties. They will come out against it," he said.
He also proposed the prime minister and cabinet ministers should not be MPs while the prime minister should be nominated and endorsed by parliament.
One of the qualifications of a prime ministerial candidate should be that he or she must not have held the top post before and should be limited to serve only one term to ensure the premier focuses on the job, Mr Paiboon said.
To uphold checks and balances between the legislature and the executive, he said the prime minister should not have the power to dissolve the House of Representatives, and parliament should not have the power to remove the premier from office.
A prime minister could be removed from the post by a court order only, he proposed, while MPs and senators could directly file charges with the court against the prime minister if the premier is implicated in corruption.
Charas Suwanmala, an NRC member dealing with local administration and a charter writer, said he is considering pushing for wider decentralisation of powers by allowing provinces to seek autonomy in some areas.
However, he said such a proposal will be limited to provinces deemed ready for autonomy though he did not elaborate on how this status would be obtained.
Meanwhile, His Majesty the King has endorsed the appointment of NRC chairman Thienchay Kiranandana and his deputies Borwornsak Uwanno and Tassana Boontong.
The National Legislative Assembly (NLA) on Thursday selected five members out of 10 candidates to serve on the CDC which is being formed. That brings the number to 25, following the NRC's selection of 20 charter writers on Wednesday.
The National Council for Peace and Order (NCPO) and the cabinet are expected to nominate five people each to the CDC when they meet on Nov 4.
The NCPO will also select the CDC chairman.