In a sharply-worded statement, centrist Potami hit out at MP Giorgos Amyras who announced his departure from the party earlier on Monday.
By leaving the party shortly before the launch of debate on the Prespes name deal, Amyras has "chosen to join the rightwing pantheon as the MP who destroyed Potami's parliamentary group," Potami said in a statement.
It added that Spyros Danellis, another Potami MP who left Potami over his differences with the leadership on the Prespes deal, had joined "the leftwing pantheon" by leaving the party to "save the Tsipras government," referring to a confidence vote last week that Prime Minister Alexis Tsipras scraped through.
"Danellis and Amyras had repeatedly pledged to hand over their seats if they were to disagree with the party," Potami's statement said, adding that Amyras had "sworn" last week that we would not leave, remarking, "I am not Danellis."
"The decision deprives our party of the ability to have a parliamentary group in Parliament," the statement said. "However it does not reduce the force of our opinions, our impact on society."