The United Thai Nation (UTN) Party is open to joining Pheu Thai's coalition after the Move Forward Party (MFP) was dropped from the line-up, according to UTN leader Pirapan Salirathavibhaga.
He was hinting at the possibility of the UTN joining the coalition if formally invited.
UTN and Pheu Thai leaders met two weeks ago to discuss terms and conditions for building a coalition.
The UTN has maintained that it will not be a member of a coalition with the MFP, citing the latter's stance to amend Section 112 of the Criminal Code, or the lese majeste law.
On Wednesday, Pheu Thai announced it had scrapped the memorandum of understanding signed between the MFP and six other political parties on the formation of a government, paving the way for a new Pheu Thai-led coalition.
The party also said the MFP would not be in the new coalition due to its stance on amending Section 112.
Mr Pirapan said a variety of factors will be considered if and when the UTN is asked to be included in the new government.
The UTN wishes for the new coalition to be promptly formed regardless of whether or not it is in the lineup.
The UTN has been criticised by the pro-democracy camp as a political vehicle for Prime Minister Prayut Chan-o-cha, whose resignation as a party member earlier was seen as helpful in easing the party into a Pheu Thai-led government.
Mr Pirapan also reiterated that the UTN is against the formation of a minority government, saying an unstable administration could do more harm than good for the country.
At this point, the UTN is undecided on whether to vote for a Pheu Thai candidate for prime minister.
The UTN is expected to support Pheu Thai's candidate if it considers the new government and its ideologies compatible.
Meanwhile, Jurin Laksanawisit, acting Democrat Party leader, said he was not aware of any formal talks planned between his party and Pheu Thai for the formation of a new government.
The Democrat Party has not yet made up its mind on whether it wishes to be in the Pheu Thai-led coalition or not, he said.
He insisted that the party strictly follows its regulations which require such a major decision to be made formally.