The Democrat Party has agreed to join a meeting next week between the Election Commission (EC) and political parties to discuss plans for a fresh general election.
The Democrats resigned en masse from parliament just before the Lower House was dissolved, and then boycotted the Feb 2 poll.
Democrat leader Abhisit Vejjajiva said the party will send representatives to the meeting, which is scheduled for Tuesday.
He did not say whether he would attend the forum personally or assign someone to go on his behalf.
The EC has invited the leaders, deputy leaders and secretary-generals of all 70 registered parties to attend the meet.
Mr Abhisit also demanded to know whether the Pheu Thai Party would send representatives with decision-making powers to the meeting.
He said the party had repeatedly sent representatives without adequate authority to previous poll discussions.
Democrat spokesman Chavanond Intarakomalyasut also accused Pheu Thai and some smaller parties of failing to make meaningful contributions to those earlier talks.
He said Pheu Thai in particular had joined the meetings only to reinforce its demand for an election to be held rather than to add suggestions, a move that was not conducive to a productive discussion.
Mr Chavanond said parties should come up with suggestions to help make an election happen and not just repeatedly push the EC to hold a fresh poll.
He said the Democrats would cooperate if the meeting would focus on how to make an election possible.
Setting the election date alone, as Pheu Thai appears intent on doing, is not the right move, he noted.
The Democrat spokesman also reiterated his call for the EC to broadcast the meeting next week to allow the public to assess each party's views.
He said if the EC agreed with the party's call for a live broadcast, it should seek cooperation from television stations.
EC secretary-general Puchong Nutrawong yesterday called on parties to send representatives with decision-making powers to attend the meeting.
"If they [party leaders] can't show up, they should send party executives or authorised representatives," Mr Puchong said.
Mr Puchong said while it is not possible to conclude when the election will take place, the EC wants to proceed as quickly as possible.
Pheu Thai legal specialist Noppadon Pattama said the party would send authorised representatives to the meeting and would not attach any conditions.
He said the party believes the best way out of the political crisis is to "let the people decide the future" through a fair and transparent election.
He insisted an election will help alleviate political conflict and allow the democratic system to move forward, regardless of how the Constitutional Court rules in its case against caretaker Prime Minister Yingluck Shinawatra. Ms Yingluck is accused of breaching the charter in her transfer of National Security Council chief Thawil Pliensri in 2011.
Mr Noppadon also said a proposal by a group of retired soldiers and state officials to invoke Section 7 of the charter and allow the Privy Council president Prem Tinsulanonda to act as a "middle man" to end the country's turmoil is unjustified.
There is no political vacuum to justify invoking the section, he said.