A rift is widening between the Move Forward Party (MFP) and Pheu Thai as they jostle over who gets the role of House speaker.
MFP deputy leader Sirikanya Tansakun on Thursday reiterated her party's stance that the MFP needed to take the post.
Aside from leading the executive branch, the party needs to lead the legislative branch to push 45 draft bills and other bills proposed by coalition partners during their election campaigns.
With the post of speaker filled by the MFP, she said she was confident the party could pursue an agenda that includes amending the constitution.
That would pave the way for drafting a new and properly democratic constitution, a priority item in the eight-party memorandum of understanding (MoU), Ms Sirikanya said.
Move Forward, and its seven allies -- Pheu Thai, Prachachart, Thai Sang Thai, Seri Ruam Thai, Fair, Palang Sangkhom Mai and Pheu Thai Ruam Phalang parties -- signed the MoU on Monday as a guideline for the policies of the government they plan to form together.
She shrugged off speculation that the rift over the post of House speaker might cause Pheu Thai to pull out of the coalition, saying she believed the party realised how important it was not to dash people's hopes for the new administration.
She also assured her party would not stab any of its partners in the back and welcomed talks on all issues of concern.
Writing on Facebook on Tuesday, Piyabutr Saengkanokkul, secretary-general of the Progressive Movement and the MFP's election campaign assistant, said that the post of House speaker is one that the MFP "can't afford to lose".
Compromises are desirable in a coalition government, but he said Move Forward should not consider giving the House speaker post away.
Pheu Thai leader, Cholnan Srikaew, criticised Mr Piyabutr's remarks, saying they were an attempt to pressure prospective coalition partners.
The House speaker is one of the most important roles in politics, overseeing House meetings and the agenda. If the MFP wants to push its legislative initiatives and fulfil its campaign promises, it needs to take control of the post, according to sources.
Another important task of the House speaker is to submit the name of a prime minister selected by parliament for royal endorsement.
Deputy Pheu Thai leader, Sutin Klungsang, said on Thursday that Pheu Thai is negotiating over the House speaker's post.
"Honour and dignity should be shared. When the MFP wants the post of prime minister, the House speaker's role should be filled by Pheu Thai," Mr Sutin said.
Pheu Thai secretary-general Prasert Chantararuangthong on Thursday reaffirmed that the party backed MFP leader Pita Limjaroenrat as prime minister. However, the post of House speaker was another matter.
"Pheu Thai confirmed its intention clearly from the beginning," said Mr Prasert. "Now, we still affirm that we will back Mr Pita as prime minister as the MFP is the leader in forming the government.
"Our stance remains unchanged. However, the post of House speaker is another matter, and it is not in the MoU," Mr Prasert said.
"Choosing the House speaker requires careful consideration. All sides must hold talks to patch up their differences," he said. "The MFP already gets the post of prime minister, so there should be no harm if Pheu Thai has a chance to fill the House speaker's role."
Adisorn Piangket, a Pheu Thai MP-elect, said Pheu Thai should take the post of House speaker, but if the two parties cannot reach an agreement, the matter should be decided by a vote in parliament.
"Do we really have to put up with someone who calls himself a friend who kicks us in the face?", Duangrit Bunnag, a supporter of Thaksin.
On Wednesday, fugitive former prime minister Thaksin Shinawatra tweeted: "Sound Familiar krub" as he retweeted a post by Duangrit Bunnag, a supporter of Thaksin and a key member of the Creative, Action, Revival and People Empowerment (Care) group.
Mr Duangrit tweeted: "Do we really have to put up with someone who calls himself a friend who kicks us in the face? A friend who keeps telling lies and stabbing us in the back.
"But we have to help him because he cannot survive on his own. If we don't help, we will be blamed. But if we help, we will suffer."
Mr Duangrit also tweeted with the hashtag: "Sometimes, patience has its limits."
A source within Pheu Thai earlier said that the party was considering Dr Cholnan, Suchart Tancha- roen and Wisut Chainaroon for House speaker.
