The Socialists and centre-right Democrats have held a monopoly on power since the end of military rule in 1974.

Their support for international bailouts and subsequent spending cuts could see their vote shrink.

Their share is predicted to slump by half to 40 per cent, meaning any winner will have to count on the support of fringe parties in parliament.

But Greece will be expected to carry on with an austerity programme if it is to continue to tap emergency loans from the European Union and the International Monetary Fund.

New Democracy leader Antonis Samaras says he will try to change the terms of a second 130 billion euro bailout if his party forms the next government.

Socialist leader Evangelos Venizelos warns that Greece has a choice between austerity or mass poverty, saying this election will determine the country’s place in Europe and the euro.