Updated

Greeks were voting Sunday in an early general election crucial for the country's financial future, with the radical left Syriza party of Alexis Tsipras tipped as the favorite to win, although possibly without a large enough majority to form a government.

Tsipras had been firmly ahead of conservative Prime Minister Antonis Samaras' New Democracy party in opinion polls leading up to the election, which is being held nearly two years ahead of time. But polls also showed a significant portion of voters were undecided two days before the vote.

Syriza has run on a campaign of renegotiating the country's 240 billion euro international bailout deal, and has pledged to reverse many of the reforms pushed through to qualify for the rescue loans that have kept Greece financially afloat for the past four years.

The anti-bailout rhetoric has renewed fears of Greece's ability to definitively emerge from its financial crisis that saw a quarter of its economy wiped out, sent unemployment soaring and hammered the euro, the currency shared by 19 European countries.

The country's creditors insist Greece must abide by its commitments to continue receiving support, and investors and markets alike have been spooked by the anti-bailout rhetoric. Greece could still face bankruptcy if a solution is not found, although talk of 'Grexit' - Greece having to leave the joint currency - and a subsequent potential collapse of the euro itself has been far less fraught than during the last general election in 2012.

Samaras' campaign focused on the gradually improving economy, which grew for the first time in six years in the third quarter of 2014, and has promised to reduce some taxes if re-elected. He has warned of the potentially dire consequences of reneging on bailout conditions — to the point that his critics accused him of running a fear campaign.

But Syriza's promises of ending the crushing austerity Greeks have been living under since 2010 have wooed many voters infuriated by the deterioration in their standard of living and ever increasing tax bills.

The big question is whether any party will win the required 151 of parliament's 300 seats to form a government alone. The Greek political scene has fractured during the financial crisis, with voters abandoning the two formerly dominant parties — the conservatives and the socialists — in favor of a smattering of smaller parties.

In their final day of campaigning Friday, both Tsipras and Samaras appealed to the undecided voters, which opinion polls put at around 10 percent in the days before the election.

Without the required 151 seats, whichever party wins will have to try forming a coalition government with another party. The first three parties each have three days to try and form a coalition government to avoid a second election being called within a month.

Another option, however, would be for the winner to seek support for a minority government, where other parties would vote along government lines without participating itself in a power-sharing deal.

Opinion polls ahead of the vote showed the new centrist Potami, or River, party vying for third place with Nazi-inspired Golden Dawn, whose leader and several top lawmakers are in jail awaiting trial on charges of participating in a criminal organization.

Whichever government emerges, it has a series of formidable tasks ahead of it, the most pressing of which is concluding frozen negotiations with bailout inspectors to release a $8.1 billion loan installment originally due late last year.

The inspectors "must come soon," Finance Minister Gikas Hardouvelis said Saturday.

The new government will also have to negotiate some kind of relief for Greece's 320 billion euro debt and bolster weak growth.