Greek Socialist leader Evangelos Venizelos has told voters that Greece may have to abandon the euro if they fail to support him in tomorrow's general election.

"Sunday will decide if we stay in Europe and in the euro ... or if we send the country down the road of bankruptcy and its people to massive poverty," Mr Venizelos said.

Mr Venizelos' last appeal before the poll echoed a warning by German finance minister Wolfgang Schaeuble, who said Greece's next government must abide by commitments Athens made in exchange for a €130bn international bailout.

"On Sunday, our people's fate is at stake," Mr Venizelos told a few thousand supporters who came to hear his final pitch for support in the Athens square yesterday in front of parliament where there have been repeated anti-austerity demonstrations, some of them violent.

The troika of IMF, European Union and European Central Bank lenders say the election could put at risk the fiscal cuts and reforms Greece must deliver in exchange for the money it needs to stay solvent and turn its economy around, including €11.7bn of new savings due in June.

Conservative New Democracy and Mr Venizelos's Socialist PASOK are the only two major parties backing the bailout and are expected to try to form a coalition after the vote to press ahead with the programme.

They will be the top two parties, but their former dominance has been sapped by anger over economic suffering and it is uncertain whether they can win enough votes to govern without external support.

A raft of smaller left and right wing anti-bailout parties vying for third place are expected to perform well in the poll, tapping into popular anger against wage cuts and record unemployment resulting from reforms demanded by the lenders.

Mr Venizelos, who negotiated the bailout as Finance Minister, said that the Socialists should not be taken for granted as a coalition partner.

The once dominant Socialists are trailing New Democracy in the polls and are expected to take less than half the number of votes they scored in the last election in 2009.

Mr Venizelos dismissed New Democracy's pledge to slash taxes and increase pensions, promising instead to soften future fiscal cuts by spreading them over three years instead of the two set out in the bailout plan.

The plan allows for an extension if the country's recession, already in its fifth consecutive year, proves deeper than expected.

Greece's €215bn economy has contracted by about 20% since 2008 in one of the worst recessions seen in postwar Europe. Gross domestic product is seen contracting by as much as 5% more this year.

Mr Venizelos reiterated his pledge not to impose new taxes or general wage and pension cuts if he wins the poll, focusing instead on reforms like opening up closed professions.

PASOK, which came to power in 2009 with nearly 44% of the vote, is expected to take only 14-19% this time.

The party ruled alone until November last year, before then prime minister George Papandreou stepped down and invited the conservatives to join a coalition that negotiated the bailout to save Greece from bankruptcy, the country's second since May 2010.