The leader of the Coalition of the Radical Left (SYRIZA), Alexis Tsipras, is due to receive at 2 p.m. the mandate to form a unity government from President Karolos Papoulias.
Tsipras is expected to turn to leftist parties first based on an agenda that rejects the EU-IMF bailout and which calls for Greece to call a moratorium on debt repayment.
The SYRIZA leader is expected to meet the head of the Democratic Left, Fotis Kouvelis, at 3.30 p.m., Ecologist Greens representative Ioanna Kontouli at 5.30 p.m. and the Social Pact president Louka Katseli at 7 p.m.
Tsipras has indicated that he will use the full three days at his disposal to talk with all the party leaders, including those of New Democracy and PASOK, but barring Chrysi Avgi (Golden Dawn).
ND leader Antonis Samaras returned the mandate, which he received first as his party gained 18.85 percent in Sunday?s elections and took top position, after about five hours on Monday. He said he was unable to reach agreement with other party leaders.
SYRIZA gained 16.78 percent at the ballot box and came in second. It won 52 seats in Parliament.
Because of the 50-seat bonus received by the first party, in this case New Democracy, there is no way SYRIZA can form a government without ND if it does not secure the support of PASOK and the Communist Party (KKE).
KKE leader Aleka Papariga has already rejected any idea of cooperation with SYRIZA, although Tsipras will meet with her to discuss the matter.
The only other option open to SYRIZA is to receive the backing of ND and PASOK, which seems unlikely.
Sources have suggested that Tsipras will present a three-point proposal to his counterparts, which will include the rejection of the bailout terms.
Leading SYRIZA MP Panayiotis Lafazanis told Skai radio on Tuesday that the party would seek for some of Greece?s debt to be written off.
?SYRIZA will ask for the debt to be renegotiated with the aim of its larger party being written off,? he said, adding that the leftist party does not recognise debt that is not sustainable and which Greeks cannot pay.
He also pledged to scrap salary cuts and emergency taxes.