A top European Union official has warned Greeks not to turn their backs on the euro currency ahead of an election which may which could decide if Greece stays in the euro zone and could spread turmoil across global financial markets.
Jean-Claude Juncker heads the group of euro zone finance ministers and says a win by anti-bailout radical leftists this weekend would have unforeseeable consequences for the monetary union.
The leftist Syriza party is neck-and-neck with the conservative New Democracy party in the opinion polls.
The Syriza leader Alexis Tsipras is threatening to tear up the punishing terms of the 130 billion euro bailout that is keeping Greece from bankruptcy.
Jean-Claude Juncker says an exit would damage the entire currency union and would send a devastating signal.
Voting will re-run the 6 May election that produced a stalemate.
Leader of the rival New Democracy party, Antonis Samaras says Greece cannot afford a third round of elections and must choose: euro versus drachma.
The pro-bailout party which narrowly led at the ballot last month, held its last big campaign rally in Athens on Friday.
Mr Samaras said that Greece would exit its financial crisis but not the euro.
The first choice the Greek people must make is: euro versus drachma, he told the rally in front of parliament in Syntagma Square.
Mr Samaras has accused anti-bailout parties of playing poker with Greece.
He pledged again to renegotiate the terms of Greece's international bailout to put the emphasis on job creation.
Syriza, an anti-bailout bloc which took second place with 16.8 % in the first election on 6 May, held its final rally in Athens on Thursday.
Unofficial opinion polls now suggest a fall in support for anti-bailout parties which would require strict austerity measures. Only one, the Communists, wants the country to abandon the euro.