Efforts to form a new Government in Greece have received a fresh blow after the leader of the moderate Democratic Left party said he would not take part in a coalition without the more radical leftist Syriza party.
Fotis Kouvelis's comments come just hours before the Greek President is set to resume a fresh round of talks with political leaders to try to persuade political leaders to form a coalition government.
If a cabinet cannot be formed by Thursday, when parliament convenes, new elections will have to be called.
Weekend opinion polls show that the anti-austerity Syriza party, would easily win a second ballot.
The power-sharing talks to create a government have dragged on, raising the spectre of fresh elections and a threat to its membership of the euro.
President Karolos Papoulias has summoned party leaders back after talks on Sunday failed to lead to the creation of a coalition government.
The conservative New Democracy party won general elections, but the poll failed to produce an outright winner. The second-placed left wing party, Syriza, has refused to join a coalition, demanding that the terms of an international bailout be scrapped or radically renegotiated.
Syriza leader Alexis Tsipras will not attend the latest meeting.
The political turmoil has taken a toll on markets across Europe
Since the election, Syriza has gained support, and in a new survey leads with a projected 20.5% of public support, pushing New Democracy to second place with 19.4%.
New Democracy and the PASOK party could form a government without Syriza, but the small Democratic Left party that would provide the required support is insisting that such a coalition would be unworkable.
“The president has invited us to a new meeting and I will attend,” Democratic Left leader Fotis Kouvelis said. “I will repeat my position, that without the participation of the second largest party, the government would not have sufficient popular and parliamentary support.
Shut out of main debt markets, Greece is surviving on rescue loans from other euro countries and the International Monetary Fund, who have repeatedly warned that payments will only continue if the country continues its draconian cost-cutting program.