Pro-bailout conservative New Democracy (ND) party leader Antonis Samaras was sworn in on Wednesday as Greece's new Prime Minister to head a coalition government currently being formed.

Samaras, winner of Sunday's general elections, visited President Karolos Papoulias and formally informed him that he has secured the needed parliamentary majority after marathon talks with two other parties ended successfully in an agreement to form a government.

Jointly, the ND party, the socialist PASOK party and the Democratic Left hold 179 seats in the 300-member strong new legislature.

"It will be a long-term government that will provide stability and hope to the country," Samaras said during the meeting broadcast live on the Greek national TV station NET. Papoulias wished him best success, noting that the new government will face difficult problems ahead.

Following the official swearing-in ceremony at the presidential mansion, Samaras visited caretaker Prime Minister Panayotis Pikrammenos for the handing-over ceremony, as talks over the composition of the cabinet and the policy platform among senior officials of parties continue.

The announcement of the list of ministers and their swearing-in ceremony could follow on Wednesday evening or Thursday, according to local media reports.

The new government could be of small size, including 15-17 ministers, with current National Bank Chairman Vassilis Rapanos as most likely to take over the critical finance minister portfolio, according to sources from coalition partners.

Samaras, PASOK's leader Evangelos Venizelos and Democratic Left's chief Fotis Kouvelis are expected to hold a meeting later on Wednesday afternoon to finalize details of the government and give directions to Interim Finance Minister Yiorgos Zannias who will represent Greece at Thursday's Eurogroup meeting.

Venizelos and Kouvelis have announced that no deputies from their parties will join the new ruling coalition, as they opt for technocrats.

The ND had supported with a similar pattern the previous six-month interim government coalition of technocrat Lucas Papademos which signed the second bailout deal with international lenders and a voluntary write-off of part of the country's sovereign debt burden.

The formation of the new government is expected to put an end to the political uncertainty prevailing in Greece since the first inconclusive general elections on May 6 that produced a fragmented parliament reflecting a divided society between pro-bailout and anti-bailout forces.

The new coalition partners have repeatedly said that their first priority will be the renegotiation of some tough austerity conditions of the two bailout deals the debt-laden country has clinched with EU counterparts and the International Monetary Fund since May 2010 to keep it afloat and in the eurozone.

The radical left SYRIZA coalition, which ranked second at a small distance behind the ND in both elections, supported a more aggressive approach to change the plan to counter the Greek debt crisis that started in late 2009.

Its call for the abolition of bailout deals alarmed international observers that Greece could be led into a disorderly default and exit from euro that would plunge the eurozone and international markets in turmoil.

Political analysts in Athens have warned that under the pressing economic woes of recession-hit Greeks, there will be no "honey moon" period for the new government which will have to amend the harshest austerity policies and push through immediately reform measures to overcome the crisis.