Pheu Thai should amend the memorandum of understanding (MoU) the eight-bloc coalition signed upon agreeing to support the Move Forward Party (MFP) in its bid to lead the new government, according to Plung Sungkom Mai (PSM).
PSM is one of the eight parties in the political alliance formerly led by the MFP but which has since fallen under Pheu Thai's stewardship.
As all 23 of the policies included in the MoU were drawn up by the MFP, and with Pheu Thai having now won the trust of all members of the alliance to assume the leading role, Pheu Thai should take this opportunity to alter it where appropriate, said Chaowarit Kachornpongkirati, a list MP and leader of the PSM.
"Since the MFP has already handed over the right to lead the formation of the new government to Pheu Thai, the old MoU is no longer valid," he said.
Pheu Thai may require changes so that it can include more parties in the bloc in a fresh attempt to win the parliamentary vote to select a new prime minister, he said.
Mr Chaowarit said he would submit the proposal at the alliance's next meeting.
He declined to comment on which parties should be included in the alliance, saying that decision would lie with the bloc's leader.
Meanwhile, Pheu Thai secretary-general Prasert Chantararuangthong said the MoU may have to be amended to bring it more in line with the party's views.
The first point in the MoU, which states that all members of the alliance are committed to supporting MFP leader Pita Limjaroenrat to become Thailand's next prime minister, for instance, might have to be changed as it appears unlikely Mr Pita still has a chance of becoming the premier, Mr Prasert said.
Any proposed changes, however, would have to be first discussed among all eight parties first and approved at a formal meeting, he added.
As for the MFP's intention to ask parliament to revise its resolution on July 19 to reject the MFP's resubmission of Mr Pita for a second parliamentary vote to select the prime minister, Mr Prasert said he would have to study in detail the MFP's new plan before commenting any further.
He denied rumours that Pheu Thai and the MFP now have a serious rift, saying he talked on Tuesday with MFP secretary-general Chaithawat Tulathon and Phicharn Chaowapatanawong, a deputy party leader, explaining why the planned meeting of the eight parties was called off.
Mr Prasert also denied exploiting talks with five parties in the caretaker cabinet last weekend to pressure the MFP to quit the bloc. He said at no time during those talks did the issue of Pheu Thai forming a new coalition with other partners come up.