The Pheu Thai Party expelled two MPs, Saranwut Saranket and Pornpimol Thammasarn, on Tuesday, according to its secretary-general Prasert Chantararuangthong.
The party convened a meeting during which Mr Saranwut was cast out by a vote of 131 in favour, two against and two abstentions. Ms Pornpimol was booted out of the party with a vote of 134 in favour to one against.
Mr Saranwut, an MP for Uttaradit, was accused by Pheu Thai of harbouring ill intentions toward the party by making scathing remarks about it after being denied a role in the previous censure debate against the government in early May.
The main opposition party was also unhappy with Ms Pornpimol, a Pathum Thani MP, for not voting with the party on crucial pieces of legislation and motions, and instead voting with the government.
The celebrated songstress also drew Pheu Thai's ire for not joining party activities or meetings.