Alexis Tsipras's left-wing Syriza party battered opponents in a snap general election as Greeks gave the 41-year-old leader a second chance to deal with the country's staggering debt and carry out major reforms aimed at modernizing its government and economy.

Defying opinion polls, Tsipras comfortably beat the conservative New Democracy party on Sunday to retain a coalition partnership with the small right-wing Independent Greeks.

"Under difficult conditions, the Greek people have given us a clear order to get rid of everything that kept us stuck in the past," Tsipras told supporters in central Athens.

"It's a great victory, a clear victory, and a victory of the people."

Syriza won 35.5 per cent of the vote based on 99.44 per cent of votes counted, the Interior Ministry said on its website.

That share gives Syriza 145 seats in the 300-seat parliament and the Conservative New Democracy, with 28.1 per cent, 75.

In a sign of widespread discontent, the turnout was 56.5 per cent. Turnout in the January election won by Tsipras was 63.6 per cent.

As well, seven per cent of votes went to the third-place Golden Dawn, a party founded as a neo-Nazi movement in the 1980s.

The vote was held as Greece struggles to cope with Europe's refugee crisis. It also faces further harsh austerity reforms as part of a massive, third international bailout that Tsipras was forced to adopt to keep the country in Europe's joint currency.

Just seven months into his term, Tsipras lost his majority in parliament after far-left rebels in his party opposed tough new conditions demanded by Eurozone countries for the 86 billion euro rescue package: Hikes in sales and business taxes, changes to public administration and labor laws opposed by unions, and further pension cuts to address the country's dramatically aging population.

Massive unemployment, debt rates

The rebels, who formed a breakaway party, failed to get elected to parliament.

"The choice appears to have been made that when push comes to shove, Syriza will opt to keep Greece in the euro. But we note this result provides a platform upon which Syriza will continue to challenge significant parts of the [bailout] program," said Malcolm Barr, an economist at JPMorgan.


Supporters of Syriza party react at the party's main election kiosk after the announcement of the first exit polls in Athens on Sunday. (Alkis Konstantinidis/Reuters)

After years of recession and tough reforms, a quarter of the country is still out of work and its national debt is worth a stunning 175 per cent of annual output. The continued hardship meant Greeks showed little enthusiasm during the brief election campaign.

Tsipras supporters early Monday appeared forgiving.

"He is young. We had been voting for the others for 40 years," said Athens resident Eva Vasilopoulou, who attended the victory rally. "We are giving [him] a second chance. He is pure, and smart, and I hope he will govern for many years."

Syriza abandoned its anti-bailout platform and billed its re-election as a blow to crony politics from more established parties, refusing to consider joining the conservatives in a grand coalition.

The new government will have a small majority of just five seats — and little time to waste.

Creditors are expected to review progress of reforms as part of the bailout next month, while the government will also have to draft the 2016 state budget. It must also oversee a critical bank recapitalization program, without which depositors with over 100,000 euros ($113,000 US) in their accounts will be forced to contribute.

A total of eight parties won parliamentary seats, including the once-dominant Socialist Pasok, centrist Potami, the Greek Communist Party and the Centrist Union — a fringe party led by Vassilis Leventis, a political pundit famous for his on screen outbursts of anger during appearances on his long-running late-night TV show.

"I've fought for 25 years to get into parliament," he said. "I stayed on my feet knowing that the political system would eventually fall apart. I had a hunch that, one day, I'd be vindicated."

with files from Reuters