Greece's conservative New Democracy party has been holding a second day of talks with the socialist Pasok and Democratic Left on forming a coalition after elections on June 17.
The deadline for a deal is June 20.
Pasok leader Evangelos Venizelos told journalists that he was "optimistic" about the discussions.
"To a large extent, we have common opinions and what is very significant now is that we speed up the process because we have to send a message abroad of stability and credibility in the country," he said. "Domestically, we have to send a message to the Greek people of security and prosperity, because the Greeks need to smile once again."
New Democracy has pledged to respect Greece's debt bailout deal with international lenders.
Based on reporting by AP and AFP