Greek Prime Minister Alexis Tsipras has conceded defeat after a partial vote count showed Greece's opposition conservatives comfortably winning the parliamentary election.
The conservative New Democracy party of Kyriakos Mitsotakis has 39.7 per cent of the vote compared to Tsipras' Syriza party with 31.5 per cent after nearly 60 per cent of ballots were tallied on Sunday.
The result was a stinging blow to Tsipras, who had insisted he could overturn a sizeable gap in opinion polls running up to Sunday's election, the first since the country emerged from its international bailouts.
"The citizens have made their choice. We fully respect the popular vote," Tsipras said in his concession speech from central Athens, adding that he had phoned Mitsotakis to congratulate him.
"I want to assure the Greek people that ... we will protect the rights of working people with a responsible but dynamic opposition," he said.
"I wish and hope that the return of New Democracy to the government will not lead to vengeance ... particularly toward the significant achievements to protect the social majority and the workers."
Official projections based on early partial results also showed the extreme right-wing Golden Dawn party teetering on the lower side of the three per cent threshold needed to be in parliament.
Golden Dawn became the third-largest party in parliament during Greece's financial crisis.
Greece is gradually emerging from the crippling financial crisis that saw unemployment and poverty levels skyrocket and the economy shrink by a quarter.
Greece was dependent for survival until last summer on three successive bailouts and had to take deep reforms such as massive spending cuts and tax hikes to qualify for the rescue loans.
Tsipras, 44, called the election three months ahead of schedule after his left-wing Syriza party suffered a severe defeat in EU and local elections in May and early June.
Tsipras led his small coalition of the Radical Left, or Syriza, party to power in 2015 on promises to repeal the austerity measures of Greece's first two bailouts.
But after months of tumultuous negotiations with international creditors that saw Greece nearly crash out of the EU's joint currency, he was forced to change tack, signing up to a third bailout and imposing the accompanying spending cuts and tax hikes.
He also cemented a deal with neighbouring North Macedonia under which that country changed its name from plain "Macedonia".
Although praised by Western allies, the deal angered many Greeks, who fear expansionist aims on the Greek province of the same name.
Mitsotakis, 51, the son of a former prime minister, brother of a former foreign minister and uncle to a newly elected mayor of Athens, had been ahead in opinion polls for three years and managed to build a sizeable lead.
He fought to shed the image of family privilege and had pledged to make Greece more business-friendly, attract foreign investment, to modernise the country's notorious bureaucracy and to cut taxes.
