"What we are doing today is the first step in bringing a variety of stakeholders to talk to each other," said lawmaker Rangsiman Rome, head of the house committee organising the two-day event. "It will pave the way for a political solution for Myanmar that is peaceful and sustainable."

Speakers include senior figures in Myanmar's shadow National Unity Government and ethnic armed organisations, but no representative from the Myanmar government.

Myanmar's foreign ministry said in a letter seen by Reuters that it "strongly objects" to parliament hosting the seminar, saying it "creates negative impacts" on bilateral relations. It asked the Thai government to tell parliament not to hold "any activity that could hinder the ongoing cordial ties".

Thai Foreign Minister Parnpree Bahiddha-Nukara was to deliver a keynote address at the seminar but cancelled at the last minute without any explanation.

The Myanmar military spokesman did not respond to a call seeking comment. The Thai foreign ministry declined to comment.

Myanmar has been in turmoil since the military seized power from an elected government in a 2021 coup.

Thailand wants to lead a humanitarian initiative by working with the Myanmar military and other groups that would pave way for talks between the warring camps.

The "Three Years After the Coup" seminar is at odds with the Thai government's preference for engagement with the junta, said Dulyapak Preecharush, a Southeast Asian studies scholar at Thammasat University.

"The parliament's committee platform has open up more space for pro-democracy groups," Dulyapak said.

(Reporting by Panu Wongcha-um; Editing by William Mallard)

By Panu Wongcha-um