Former socialist heavyweight Yiannis Ragousis announced his candidacy for the helm of Democratic Alignment on Wednesday.
Potential contenders in the Democratic Alignment leadership election will have to declare their candidacy by September 15, Kathimerini reports, adding that campaigning will last for six weeks.
Widely seen as the political reincarnation of once-dominant PASOK socialists, the nascent center-left party aspires to occupy the vast political space between ruling SYRIZA and conservative New Democracy opposition.
PASOK leader Fofi Gennimata, Athens Mayor Giorgos Kaminis and former socialist minister Yiannis Ragousis have so far said they will run for the post. Stavros Theodorakis of the centrist To Potami party is also expected to take part in the race.
According to sources, candidates will face each other in several nationwide debates, while voters will be able to cast their ballots on electronic systems without a paper trail, as well as by mobile phone.
The procedure is overseen by Nikos Alivizatos, a professor of constitutional law.