Deputy Prime Minister Prawit Wongsuwon has welcomed the so-called "Three Allies" group's pledge to join the Phalang Pracharat Party and voiced confidence Prime Minister Prayut Chan-o-cha will get the chance to "carry on" after the next election.
Gen Prawit said it was a good sign that the group was joining Phalang Pracharat and backing Gen Prayut.
The group's pledges would help the country be strong and stay strong, he said.
Key members of the Three Allies are former transport minister, Suriya Jungrungreangkij, former industry minister, Somsak Thepsuthin, as well as former deputy education minister, Chalong Krudkhunthod, ex-MP for Chai Nat, Anucha Nakasai, and former Nakhon Ratchasima MP, Pirom Polwiset.
Gen Prawit said he has always rallied behind Gen Prayut.
"Let us see what will happen. I have confidence Gen Prayut will be able to carry on [after the election]. I always support him," the deputy premier said.
He was understood to be referring to Gen Prayut's chances of returning as prime minister after the next election expected in February next year.
Gen Prawit's comments followed a Three Allies group gathering at the Pinehurst Golf & Country Club on Wednesday.
The event was attended by about 50 former MPs. Many were formally with the Thai Rak Thai and People's Power parties, that were dissolved by the Constitutional Court for electoral fraud. Some members are from the Pheu Thai and Bhumjaithai parties.
It was reported the gathering was moved forward from Saturday to Wednesday.
Mr Suriya told group members that he was throwing his support behind Gen Prayut to return as prime minister.
He said he has contacted key government figures including Deputy Prime Minister Somkid Jatusripitak, Commerce Minister Sontirat Sontijirawong and Industry Minister Uttama Savanayana to say he was willing to help Gen Prayut, although he disliked the military coup.
Mr Suriya said his name has been dragged through the mud since being accused of involvement in alleged price manipulation and kickbacks in the multi-billion-baht import of 26 CTX baggage scanners for Suvarnabhumi airport.
However, the National Anti-Corruption Commission decided in 2012 not to pursue the case against 28 suspects, including fugitive former premier Thaksin Shinawatra and Mr Suriya, citing insufficient evidence.
The former transport minister said he had only been with one party throughout his political career, Thai Rak Thai founded by Thaksin.
"Whatever party I'm with is sure to be in the government," he told the gathering.
Mr Suriya said the group members should head back to their constituencies and gauge local peoples' needs so they can be incorporated into a policy plan to be presented to Phalang Pracharat for consideration.
In Nakhon Ratchasima on Thursday, the Phalang Korat group comprising the province's former MPs was formed and pledged allegiance to Phaland Pracharat. Its leading members include Suporn Atthawong, a former key figure of the red-shirt United Front for Democracy against Dictatorship, and former Pheu Thai member Somchai Phetprasert.
Mr Pirom said Phalang Korat was hooking up with Phalang Pracharat in the hope the party could lead the next government and continue the mega infrastructure projects which the present administration has launched.