The campaign for rewriting the charter has kicked off as two draft amendments were submitted to parliament President Somsak Kiatsuranon yesterday.
The first draft is sponsored by the Pheu Thai-led government and the other by the red-shirt United Front for Democracy against Dictatorship.
Both seek to amend Section 291 of the constitution to create a Constitution Drafting Assembly.
Next week, the coalition Chartthaipattana Party plans to submit its own version seeking the formation of a charter rewrite body as well.
The government's draft, backed by 275 MPs, is expected to be put on the docket within 15 days. Parliament will take about two months to verify all the names of the supporters of the UDD's measure which came with the signatures from more than 60,000 people.
Government chief whip Udomdet Rattanasathien said it does not matter how many drafts are tabled for scrutiny.
He promised the government would not seek to amend Section 112 of the Criminal Code, known as the lese majeste law.
"Pheu Thai commands a majority in the House and it affirms that it will not amend Section 112," he said.
Pheu Thai MP Weng Tojirakarn, also a core UDD member, said the UDD draft is better than the Pheu Thai's version in terms of the selection of CDA members. Following the Pheu Thai's draft, there would be 99 CDA members _ 77 from elections in each province and 22 from the selection of academics. The UDD-proposed CDA comprises 100 members who will be selected from all provinces.
However, it demands proportional representation in which large provinces such as Bangkok and Nakhon Ratchasima may have more than one member.
Mr Weng said that he disagrees with the party's draft which calls for the appointment of 22 academics as part of the CDA. He said that most academics are deemed conservatives and their input may make the constitution undemocratic.
But Mr Weng brushed aside concerns the CDA might be dominated by nominees of political parties because the draft amendments fail to ban politicians from taking part in the process.
He challenged those who believe they are qualified to be CDA members to apply. The UDD leader said that he expects the selection of the CDA to be completed this year.
Both drafts share other similarities. They do not bar politicians from taking part in the charter rewrite process and demand a charter to be put up for referendum after its completion.
However, the government's bill calls for the drafting process to be completed in 180 days, while the UDD's version requires that it be completed in 240 days.
Chartthaipattana MP Paradon Prissanananthakul said the party will submit its draft next week.
He said the key difference is the party's version calls for the draft charter to be scrutinised by parliament first.
Meanwhile, a Sripathum Poll found a majority of 1,700 respondents did not see the charter amendment as a priority.