Suthep Thaugsuban's lawyer on Friday applied to register a new political party in which the founders' list includes the veteran politician's younger brother Thanee, with Mr Suthep its likely adviser.
Thaweesak na Takuathung filed an application for the registration of the Ruamphalang Prachachartthai (Uniting the Force of the Thai Nation) at the Office of the Election Commission.
The lawyer said he was among the 32 founders, which also included Thanee Thaugsuban, Mr Suthep's brother.
Academic Anek Laothamatas, a drafter of political reforms and former leader of the Mahachon Party, was not included in the founders' list. Mr Anek was expected to lead the new party.
Mr Thaweesak said the complete list of people involved in the new party would be made known when the founders meet in June.
He had consulted with Mr Suthep in forming the party, and Mr Suthep could be an ordinary member or adviser of the new party in the future.
Mr Thaweesak denied the new party would serve the orders of Mr Suthep or be a branch of the Democrat Party, of which Mr Suthep had formerly been a leading member. He also denied that the new party was an offshoot of the now-defunct People's Democratic Reform Committee (PDRC) that Mr Suthep had earlier led in street protests to oust the Yingluck Shinawatra government.
Representatives of the Ruamphalang Prachachartthai group had sought approval from the National Council for Peace and Order for a party founders' meeting at Lumpini public park in Bangkok on June 3. It also asked for permission to conduct nationwide campaigns from June to August, he said.
A general assembly was planned at Lumpini park on Sept 2 for the election of the party executive.
Pheu Thai Party acting spokesman Anusorn Iamsa-ard pointed out that Mr Suthep had earlier announced he was quitting politics.
Forming a political party to compete in a democratic fashion was beneficial for the people, increasing the choices available to them, but players should be transparent. They should admit it is the PDRC's party, he said.
The Pheu Thai spokesman also said the new party would have an effect on the Democrat Party because they had a similar voter base.