The Pheu Thai Party and the Move Forward Party (MFP) have agreed to nominate Wan Muhammad Nor Matha, leader of the Prachachat Party, as House speaker, ending a bitter battle over the post.
At a press conference on Monday evening, MFP leader Pita Limjaroenrat said the two parties agreed to nominate Mr Wan Nor for the House speakership, an MFP MP as the first deputy speaker and a Pheu Thai MP as the second deputy speaker.
The eight prospective coalition parties agreed to this proposal, he said.
Six coalition parties were excluded from the press conference at the last minute after Pheu Thai told the MFP that the matter was between the two parties.
Deputy Pheu Thai leader Phumtham Wechayachai said on Monday that Mr Wan Nor was acceptable to all sides, and both parties agreed that this would end the deadlock over the post.
He said the most important thing was to maintain unity in order to form a democratic government.
Pheu Thai leader Cholnan Srikaew assured that the party's MPs would not nominate anyone to compete with Mr Wan Nor.
The press conference was held after Pheu Thai proposed giving the House speaker post to Mr Wan Nor, to break the impasse over the appointment during an internal meeting on Monday.
Party MPs and executives met earlier in the day to discuss the issue and resolved that the post should be given to a third party and that Mr Wan Nor, a veteran politician and former House speaker, was best suited for the role.
Mr Wan Nor became Pheu Thai's choice after Pheu Thai and the MFP were unable on Sunday to end the deadlock in their meeting with the other six prospective coalition parties. They managed to reach a formal agreement before the House convenes to vote for a new speaker today.
Last week they discussed letting Pheu Thai take the lead in forming the new government if Mr Pita's bid to become prime minister failed. In return, Pheu Thai would step back and let the MFP take the House speaker role.
Both parties locked horns over the post as soon as the results of the May 14 general election became clear. The MFP wanted MP for Phitsanulok, Padipat Suntiphada, to be the new House speaker, while Pheu Thai stood firm in its belief that it deserved the seat of the head of the legislative branch.
Following yesterday's internal meeting, Pheu Thai told media outlets to wait for a joint press conference from the eight-party alliance at 7pm after the official opening of parliament.
After learning of Pheu Thai's offer, Mr Wan Nor said that he did not want the job, but he would take it if it could move the formation of the coalition forward, and it was agreed by the two parties and the other partners.
"I'm willing to take the post if they reach an agreement," he said.
The Prachachat Party, which won nine House seats in the general election, was the third-largest party in the eight-party bloc, and a source said Pheu Thai's move to back Mr Wan Nor could defuse tensions in the party because several factions were eyeing the post.
According to the source, Pheu Thai's refusal to cave in gave the MFP two choices: accept the proposal or withdraw from the alliance to become the opposition.
The source said if the MFP went with the first choice, its leader, Mr Pita, might not get the prime minister post, but it could negotiate for key ministries to drive its core policies. However, controversial ones, including amending Section 112, or the lese majeste law, would likely be shelved.
Meanwhile, former House speaker and Democrat list-MP Chuan Leekpai on Monday expressed his support for Mr Wan Nor, saying the Prachachat leader had already proved capable of doing the job. He said he had worked with Mr Wan Nor, who is known to be able and impartial.