Seventy-two senators and MPs on Monday asked parliament to seek a Constitutional Court review of three charter amendment proposals including the version sponsored by civil group iLaw before a vote is held.
In a motion proposed by Senator Somchai Sawaengkarn and Palang Pracharath Party (PPRP) MP Paiboon Nititawan, the group said they were concerned the three drafts, which seek to pave the way for the drafting of a new charter, may be unconstitutional.
The motion was signed by 47 senators and 25 MPs, all from the main coalition party, the PPRP, who claim parliament is not authorised to "make" a new charter and the most it can do is to make changes.
"So any action to allow for the writing of a new charter is deemed unconstitutional," read the motion.
The move to seek a ruling on the three drafts came after parliament was scheduled to scrutinize six such proposals next week. The iLaw-sponsored draft was expected to be tabled for examination later this month.
Senator Kittisak Rattanawaraha said on Monday the move was not aimed at delaying the amendment process, but it was to make sure the process was in accordance with the constitution.
He also said the senators were concerned that they would face a malfeasance charge if they voted in favour of charter proposals that were later found to be unconstitutional.
"The senators' job is to make sure that the lawmaking process abides by the constitution," he said.
He said the iLaw draft, which was supported by more than 100,000 people, was also a cause for concern after the group admitted it had received financial support from overseas.
Deputy Pheu Thai leader, Chusak Sirinil, said on Monday the move was premature, noting that they could seek the court's ruling once the bills had gone through parliament.
Asked if the move would stall the charter amendment process, Mr Chusak said it would depend whether the court accepted the petition for consideration.
Meanwhile, Senator Kamnoon Sidhisamarn wrote on Facebook on Monday he would not vote for the iLaw draft which calls for the abolition of seven out of 10 organic laws written under the 2017 charter.
The seven laws involve the Senate, the procedures of the Constitutional Court, the Election Commission, the Ombudsman, graft and corruption, state auditing, and the national human rights body.
Sen Kamnoon said while the iLaw draft would allow members of all public independent organisations to assume acting roles, these bodies would be left without authority as organic laws governing them would temporarily no longer exist and the country would be without a mechanism to fight graft for six months.
The Senate election process would take at least 60 days, followed by the selection of public independent agencies. Then new organic laws would be drafted, which would take at least another 90 days, he said.
"When considering the whole draft, I can't bring myself to vote for it, especially considering that the country would be without a law to fight corruption for six months," he said.