FACING a fateful decision on how to vote in today's general election, Greeks yesterday weighed their anger at five years of biting recession against a deep fear of being forced out of Europe's single currency.

Today's vote amounts to a referendum on the punishing terms set by international lenders as the price of saving debt-ridden Greece from bankruptcy – tax hikes, job losses and pay cuts that have condemned the country to record-breaking recession.

Riding a wave of anger that has taken him from political obscurity to contender for power, radical leftist Syriza leader Alexis Tsipras, 37, is threatening to tear up the bailout deal, saying Europe is bluffing when it threatens to cut Greece loose and risk a broader euro break-up.

On the right, establishment heir and New Democracy leader Antonis Samaras, 61, says that to reject the €130 billion bailout deal would force a return to the drachma and even greater economic calamity.

Wrapping up his campaign on Friday night before several thousand supporters waving Greek and EU flags in the capital's central Syntagma square, Samaras said: "We are going into an election to decide the future of Greece and of our children."

The vote is a re-run of the May 6 election that produced stalemate, when anger at the close-knit and often corrupt political clique that has run Greece for years propelled Syriza from the fringes into second place.

"My heart says I should vote for the left, for all the horrible things these [mainstream] politicians have done to us, but my mind says vote for the right, so that Greece does not leave the euro," said part-time teacher Kostas Manitsas, 28.

A Syriza victory today could sow turmoil on global financial markets, just as leaders of the Group of 20 world economic powers gather in Mexico for a meeting dominated by the crisis.

"Sunday's vote must not be based on anger but on hope," the liberal left daily Ta Nea implored in an editorial. "It must be based on the Greece of the euro, not the Greece of the drachma."

Greeks say they want to keep the euro, but do not want the pension, wage and jobs cuts imposed by the bailout package and which have seen living standards plummet and unemployment reach almost 23%.

The country's lenders in the European Union and International Monetary Fund say they cannot have one without the other.

"Public opinion polls, as well as the May 6 vote, show that those who want the euro overwhelmingly outnumber those who reject it or are willing to sacrifice it for their own party-political purposes," wrote the centre-left daily Ethnos.

Opinion polls published before a ban two weeks ago put the two parties almost neck and neck. Neither is expected to win outright, triggering coalition talks.

Eurogroup head Jean-Claude Juncker urged Greeks not to turn their backs on the euro, for their own sakes as well as the sake of the 17-member currency union, with the far larger economies of Spain and Italy also on the ropes.

"If the radical left wins – which cannot be ruled out – the consequences for the currency union are unforeseeable," Juncker, head of the group of eurozone finance ministers, told Austrian paper Kurier.

"We will have to speak to any government. I can only warn everyone against leaving the currency union. The internal cohesion of the eurozone would be in danger."