Key representatives of opposition parties share their views on the constitution in front of the Pattani provincial hall in Pattani province on Sept 28. (Photo from the Pheu Thai Party)

The Internal Security Operations Command has filed a sedition complaint against 12 people, including several opposition party leaders, following their recent public discussion in the far South on changes to the constitution.

Maj Gen Burin Thongpraphai, legal officer of the Isoc southern forward command, said on Friday that he filed a complaint at Pattani police station, in Pattani province, on Thursday against 12 people. They included Sompong Amornwiwat, 78, leader of the opposition-core Pheu Thai Party, and Future Forward Party leader Thanathorn Juangroongruangkit, 40.

He took the legal action on behalf of the chief of the 4th Army Region, which supervises the South.

Maj Gen Burin was the point man for countless legal actions filed against critics of the military junta during its five-year rule prior to this year's elections.

Seven opposition parties organised the discussion in front of the Pattani provincial hall on Sept 28.

The forward command alleges that the discussion affected national security and solutions to problems in the southern border provinces.

Those accused also include Chalita Banthuwong, lecturer in social science at Kasetsart University, who proposed an amendment to Section 1 of the constitution which prohibits separating the country.

Others are Prachachat Party leader Wan Muhammad Nor Matha, 75, his deputy Muk Sulaiman, 70, Puea Chat Party leader Songkhram Kitlertpairote, 75, Thai People Power Party leader Nikhom Boonwiset, 49, Lt Gen Paradon Pattanatabut, 64, former secretary-general of the National Security Council, Sompong Sakawee, 69, Rakchart Suwan, 55, Asama Mangkonchai, 45, and Sirote Klampaibul, 48.

About 150 people attended the discussion which was livestreamed on the Facebook page of the Prachachat Party and also posted on the YouTube video portal.

The Isoc complaint cited Section 116 of the Criminal Code, which bans sedition and stipulates a jail term of up to seven years for violation.

The 12 people are accused of distorting facts in a way that could cause public disobedience, said Maj Gen Burin, who was until recently legal affairs chief of the coup junta's now-defunct National Council for Peace and Order.