Exit polls have projected that Greece's former majority socialist party has been pushed down to third place in the country's parliamentary elections, with no definitive frontrunner and no party gaining enough votes to form a government.
The left-wing PASOK party saw its share of the vote fall to 14-17 per cent from 43.9 per cent on Sunday, according to the poll, commissioned by four major television stations and carried out by three polling agencies.
The conservative New Democracy party (ND) mustered the most votes with 17-20 per cent of the vote, but it was not sufficient to give it absolute majority and was down from 33.5 per cent at the 2009 election.
Al Jazeera's Barnaby Phillips, reporting from Athens, said: "On the face of it, this seems like massive repudiation of Greece's political establishment."
While the two pro-austerity parties suffered major losses, the leftist Syriza party, which opposed European Union-IMF reforms, jumped to second place after scoring 15.5-18.5 per cent of the vote, up from 4.6 per cent three years ago.
Golden Dawn, a neo-Nazi party, was also set to enter parliament for the first time in nearly 40 years, notching up 6-8 per cent of the vote.
The communist KKE party scored 7.5-9.5 per cent, compared to 7.5 per cent in 2009, the exit polls showed.
Both PASOK and ND have said they want the "troika" of the European Union, International Monetary Fund and European Central Bank to cut Greece more slack in their two bailout deals worth $314bn.
But with voters angry at the austerity cuts demanded in response, many of the smaller parties, including Syriza, want to put an end to the agreements, while KKE wants Greece to leave the eurozone.
Voters angered by two years of austerity measures in return for the bailouts have deserted the main parties in massive numbers, turning instead to a series of smaller parties.
If no party wins enough votes to form a government, whichever party wins the most votes will have to seek a coalition with rivals. The first party will have three days in which to conduct coalition negotiations.
If it fails, the mandate will go to the second party for a further three days, and then on to the third party.
If no coalition emerges, then the country will have to go to another election, a prospect which has alarmed Greece's international creditors.
Greece must take yet more austerity measures next month to ensure it meets fiscal targets laid out in its international bailout and to ensure the rescue loan funds keep flowing.