An MP from the ruling Palang Pracharath Party has called on three opposition party leaders and two MPs to resign over their involvement in a forum on charter amendment.
Sira Jenjaka also threatened to start a House petition calling for an ethics probe targeting the politicians if they refuse to quit.
The ruling party MP on Tuesday demanded that Pheu Thai Party leader Sompong Amornwiwat; Future Forward Party chief Thanathorn Juangroongruangkit; Prachachat Party leader Wan Muhammad Nor Matha; Puea Chat Party MP Songkram Kitlertpairoj; and Palang Puang Chon Chao Thai Party MP Nikom Boonwiset resign for participating in the forum in front of Pattani provincial hall on Sept 28.
The forum heard from an academic speaker who expressed her views on changing Section 1 of the constitution, which stipulates that Thailand is one indivisible kingdom.
Mr Sira said the exchanges during the forum contained distorted information about the charter which could possibly lead to social unrest.
The five politicians, Kasetsart University social scientist Chalita Banthuwong and six other speakers at the forum subsequently saw a sedition complaint filed against them by Maj Gen Burin Thongpraphai, legal officer of the Internal Security Operations Command (Isoc) Region 4 forward command.
Opposition parties later hit back by lodging a police complaint against Pol Maj Gen Burin and 4th Army Region commander Lt Gen Pornsak Poonsawat, on whose order the major general was acting. The opposition want the two generals charged with filing false charges and defamation.
Yesterday, Mr Sira said if the five politicians did not resign, he would gather signatures from 50 MPs to call for a probe into their actions by the National Anti-Corruption Commission for advocating changes to Section 1 of the charter.
He said the fact that they were present at the forum and listened to Ms Chalita express a view in favour of changing Section 1 justified initiating an ethics probe.
Earlier, the Rak Siam Federation asked the Election Commission (EC) to dissolve the parties the forum attendees came from.
EC secretary-general, Pol Col Jarungvith Phumma, said the actions of individual party members or leaders could not be assumed to reflect the stance of their respective parties.