World powers have raised the pressure on Greece to form a government quickly, as coalition talks loom after parties backing an EU-IMF bailout won an election that eased fears of a eurozone exit.
The European Union said Greece now had to enact key reforms after its second general election in two months handed victory to the conservative New Democracy party, which has pledged to keep Greece in the euro.
New Democracy leader Antonis Samaras, a Harvard-educated former foreign minister, said after Sunday's win: "The country does not have a minute to lose."
"We ask all political forces which share the aim of keeping the country in the euro ... to join a government of national unity."
The third-placed socialist Pasok party has said it is ready to join a coalition with New Democracy but wants other leftist forces to be included in a government of "national responsibility" with a broad mandate for reforms.
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Relieved Asian markets surged on the news with Tokyo closing up 1.77 per cent on Monday and Hong Kong climbing 1.55 per cent.
The euro also rose sharply to $US1.2720 ($A1.26) compared to $1.2644 late on Friday.
The anti-austerity leftist Syriza party and its firebrand leader Alexis Tsipras came second and has ruled out joining a coalition, arguing that the harsh conditions for the bailout deal should be scrapped altogether.
With nearly all the votes counted, New Democracy came first with 29.6 per cent of the vote and 129 of the 300 seats in parliament.
The radical left anti-bailout Syriza party had 26.9 per cent and 71 seats; and the pro-bailout socialist PASOK party came in third with 12.3 per cent of the vote and 33 seats.
The extreme far-right Golden Dawn party remained steady in public support with 6.9 per cent of the votes and 18 seats.
While official results showed that no party had won enough seats to form a government on its own - just as in the May 6 elections - New Democracy and PASOK have won enough seats to form a coalition.
New Democracy will get the first chance to broker a partnership on Monday. It requires 151 seats to form a government. If it fails, the second-placed party will get that opportunity.
Sunday's election was seen as a referendum on tough austerity measures demanded by international lenders and many economists feared a Greek exit could spark a eurozone panic.
In a joint statement European Commission President Jose Manuel Barroso and European Council President Herman Van Rompuy hailed the result, and expressed hope that a government would be formed quickly.
German Chancellor Angela Merkel was the first European leader to call Samaras, saying she would work together with him "on the basis that Greece will meet its European commitments."
Tsipras accused Samaras during the campaign of defending "Merkel's Europe of the past" while Samaras said Tsipras would bring back the drachma currency.
The US stressed that it was in everyone's interests "for Greece to remain in the euro area".
Any new government in Greece faces daunting economic challenges in a country where unemployment is 22.6 per cent and a tricky political balancing act between pressure from the streets and from the global financial community.
Victory celebrations were extremely muted in Athens on Sunday with just around 100 New Democracy supporters showing up at a victory rally with Samaras in central Syntagma square, the scene of multiple anti-government protests.
Although the immediate risk of a eurozone exit has receded with Syriza's defeat, some analysts have warned that the stricken country could eventually still have to leave the euro even with a New Democracy-led government.
Greece has been forced to seek bailouts twice, first for 110 billion euros in 2010 and then for 130 billion euros this year plus a 107 billion euro private debt write-off -- for a total of 347 billion euros.
