Members from Greece's ruling Syriza party have decided to break away and form a new party, the media reported on Friday.
Prime Minister and Syriza leader Alexis Tsipras stood down on Thursday, paving the way for snap elections, BBC reported.
The move for the new party came after Tsipras lost the support of many of his own MPs in a vote on the country's third new bailout deal where in exchange for another 86 billion euros ($95 billion) from European partners, he had to agree to state sector cuts, including far-reaching pension reforms - and keeping Greece in the eurozone.
According to a report by state-run Ta Nea daily, 25 opposing Syriza MPs will join the new party, called Leiki Anotita (Popular Unity).
The party will be led by former energy minister Panagiotis Lafazanis, who has strongly opposed the new deal.
Syriza had won 149 seats in Greece's 300-seat parliament in the last election in January. The conservative New Democracy party came second, with 76 seats. Popular Unity party will become the third largest in parliament.
The election - fifth in six years - is expected to take place on September 20.
