Gothom Arya said the draft charter would be backed in a public referendum if the Constitution Drafting Committee resolved some issues.

"I believe people will agree with having elected senators. In my view, the single-MP constituency system is also better than the multiple-MP system," he said.

With the first draft completed yesterday, 12 anti-coup groups gathered at Parliament to oppose the new constitution and vowed to vote against it.

Protesters led by the September 19 Network and Thai Say NO group claimed the constitution was designed to benefit the drafters, not the public.

Politics lecturer Giles Ji Ungpakorn, a key member of the September 19 Network, said the new constitution would reduce democracy.

"An obvious example is appointing senators and not electing them. The drafters also increased the budget for the military but limited the budget for poor people. It proves that the draft is to benefit the military and businessmen, not the people," he said.

Chanakarn Phandermwong, a coordinator of the September 19 group, said the constitution had been drafted to increase the power of government officials.

She said the draft also attempted to restore Article 7 of the previous constitution by giving authority to leaders of national organisations to resolve the problems of the country.

Members of Thai Say No gave handbooks to people advising them to vote against the draft in the referendum.