Almost half of the groups invited to Monday's talk on a possible amnesty for political offenders have pulled out after questioning the motives of the dialogue.
The chances of the talk yielding results look increasingly bleak following their withdrawal.
The talk, hosted by deputy House Speaker Charoen Chankomol, follows an unprecedented meeting between leaders of the red-shirt United Front for Democracy against Dictatorship (UDD) and anti-Thaksin People's Alliance for Democracy (PAD) on Feb 7 to discuss the issue of an amnesty.
Mr Charoen followed up by inviting more groups, including political parties, military representatives and people affected by street riots, to join the second round of meetings to forge a consensus on who should be granted an amnesty.
But critics have questioned Mr Charoen's intentions behind pushing for the dialogue, suspecting it is politically motivated.
Mr Charoen invited representatives from 11 groups, including the Pheu Thai Party, the Democrat Party, the Bhumjaithai Party, the armed forces, PAD, UDD and Pitak Siam. Also invited are Nicha Hiranburana Thuwatham, representing families of state officials killed on duty at political rallies; business operators affected by political violence; the defunct Truth for Reconciliation Commission; and the multi-colour group, led by Tul Sitthisomwong.
However, five of these groups - the Democrats, PAD, Pitak Siam, Ms Nicha and Dr Tul - have announced they would boycott the meeting. Bhumjaithai Party said Sunday it has yet to make a final decision on whether to join.
The Democrats announced on Saturday that they would not join the Charoen meet because they believe the move is part of a Pheu Thai plot to have deposed premier Thaksin Shinawatra included in the amnesty scheme.
PAD spokesman Parnthep Pourpongpan said he would not attend as the discussion failed to include all stakeholders. "The PAD will take part only if all political groups are present," he said.
Mr Parnthep disagreed with the submission of an amnesty bill by 42 Pheu Thai MPs, led by Worachai Hema, to House Speaker Somsak Kiatsuranont last week. He said the bill has a hidden agenda, which is to absolve Thaksin.
Thaksin was sentenced in absentia to two years in jail in 2008 by the Supreme Court after he was found guilty of abusing his authority in helping his former wife Khunying Potjaman na Pombejra buy plots of land on Ratchadapisek Road.
Anti-Thaksin multi-colour group leader Dr Tul said it is not an appropriate time to talk about an amnesty. His group wants to see the prosecution of wrongdoers, especially those who instigate violence in street protests, before starting talks about who should be pardoned.
"The amnesty bill will only interrupt the judicial process," he said Sunday.
Green Politics Group coordinator Suriyasai Katasila believes Monday's meeting will fail because it is driven by politicians with hidden agendas who have failed to gain the trust of the public.
However, Mr Charoen said political parties cannot be excluded from the amnesty process as their MPs are the people who are authorised to enact laws.
Participants in Monday's meeting will be asked to consider whether people who face criminal charges should be included among those entitled to an amnesty, he said.
Mr Charoen also aims to have participants discuss the contentious proposal to draft another amnesty bill, this time for protest leaders.
He said this would probably lead to a debate on the conditions of such an amnesty, for example, whether protest leaders facing criminal charges should be included in the bill.
He said he was aware that Pitak Siam and the Democrats would not send their representatives to the meeting, but the dialogue will continue as representatives from other groups will still be present.
Mr Charoen tried to distance his amnesty talks from both Mr Worachai and the Pheu Thai-led government. He insisted his attempt to mediate talks among all groups is strictly an initiative of House legislators.
"I have seen more than enough of the social division," he said. "I have no hidden agenda. I just want all sides to talk to each other."
Pheu Thai spokesman Prompong Nopparit said his party supports Mr Charoen's move and blamed the Democrat Party for "lacking sincerity" on the amnesty issue. Democrat leader Abhisit Vejjajiva earlier said he supported an amnesty for people who staged peaceful protests but were charged with violating the emergency decree.
Defence Minister Sukumpol Suwanatat said he had instructed army chief Prayuth Chan-ocha to send two representatives from the army to attend Monday's meeting.