Democrat deputy secretary-general Chanin Rungsang has called on party leader Chalermchai Sri-on to reconsider his decision to stay in the government following the scandal caused by a leaked call between Prime Minister Paetongtarn Shinawatra and Cambodian Senate President Hun Sen.
Mr Chanin said a resolution was passed on Thursday night by the party's executive committee which considered whether it should stay on as a member of the coalition government led by the Pheu Thai Party.
The party decided to stay as a coalition partner without condition despite widespread public concerns regarding the PM's competence and maturity after the widely shared conversation in which Ms Paetongtarn appeared unusually deferential to Hun Sen.
The decision has disappointed party members, resulting in a wave of resignations, Mr Chanin said. He did not provide details of the others who have supposedly quit.
However, one person who declared his stance openly against staying any longer is Napaphon Jeerakul, Bangkok councillor for Bangkok Noi district, who said he has been working tirelessly for people in the district for many years now.
Mr Chanin said the party still has time to reverse the decision and ask some difficult questions of the prime minister.
"The initial meeting might have been rushed, which meant many members of the party's executive committee did not receive comprehensive information or fully understand the public's concerns," he said.
A second meeting should be held to thoroughly review this matter, and inform a unified response that more accurately reflects the party feeling about the incident, he said.
Meanwhile, Mr Napaphon posted his resignation on Facebook, explaining that he and his family have always supported the Democrat Party.
Entering politics in 2002 with the backing of Ongart Klampaiboon -- whom he sees as a role model -- he said has worked with honesty and effort.
"The current situation involving territorial issues between Thailand and Cambodia has made it clear the leader of our government lacks both transparency and statesmanship," he wrote.
"Yet the party has resolved to continue its role in the coalition. As a member, I believe this stance violates the core ideology that all party members are duty-bound to uphold."
"Therefore, I have formally submitted my resignation as the nation must come first," he said.