Updated, 14:08

THE LEADERS of Greece’s second-largest and third-largest political parties are to meet later this afternoon in a last-ditch effort to lay the foundations for a national unity government.

Evangelos Venizelos, the leader of the socialist PASOK party, will meet with Alexis Tsipras from the Syriza coalition of radical left-wing groups, after the leader of the smallest party in the new parliament ruled out sharing power with PASOK or New Democracy, the two main pro-bailout parties.

Unless the two parties can agree a common platform from which to build a national government, it is almost certain that Greece will face a second election in order to try and resolve the political deadlock.

Fotis Kouvelis, whose Democratic Left party gained 19 seats in last Sunday’s election, this morning pulled out of talks with PASOK, which had been in government when Greece was forced into needing two EU-IMF bailouts.

“We have made it clear, the Democratic Left party will not take part in a (coalition) government of New Democracy and PASOK,” Reuters quoted Kouvelis as saying.

Reports said Kouvelis now believes repeat elections will be unavoidable unless Syriza, which came second in last week’s vote, changes its stance.

Syriza has already tried, unsuccessfully, to cobble together a coalition earlier this week.

Assuming Syriza and PASOK cannot agree a common stance – and perhaps even if they do – Greece will face a new set of elections will be held early next month, with President Karolos Papoulias appointing a judge to run an interim cabinet in the meantime.

If the parties do manage to cobble together the basis for a coalition, they will also require the backing of other parties before they can govern: between them, PASOK and Syriza command only 93 of the 300 seats in parliament.

PASOK and the other main pro-bailout party, the centre-right New Democracy, both lost seats in last Sunday’s election, leaving them two seats short of a 151-seat majority in the 300-member chamber.

More: Uncertainty continues as power-sharing talks enter third round