Greece is in the throes of final campaigning before the parliamentary election re-run on Sunday, brought about by an inconclusive vote in May.
In the second parliamentary election in just over a month, the BBC reports that the stakes are high for the eurozone, as the anti-austerity, left-wing bloc Syriza is expected to do well.
Latest official opinion polls show that Syriza, a radical left wing party led by Alexis Tsipras, is tied with the conservative New Democracy, the pro-bailout conservative party.
New Democracy narrowly led at the ballot last month, is due to hold its last big campaign rally.
Syriza held its final rally in Athens on Thursday, when unofficial opinion polls suggested a fall in support for anti-bailout parties, the BBC reports.
Under Greek election law, official opinion polls are banned in the two weeks before the election.
Tough austerity measures were attached to the two international bailouts awarded to Greece, an initial package worth 110 billion euros in 2010, then a follow-up last year worth 130 billion euros.
While five of the seven main political groups reject the latest bailout, only one - the Communists - wants the country to abandon the euro.
Germany, which has the eurozone's most powerful economy, insists that Greece, like other member-states which have received international bailouts, must abide by the austerity conditions.
German Bundesbank (central bank) chief Jens Weidmann repeated the warning on Friday, adding that the eurozone could not allow any country to "blackmail" it with the threat of financial contagion.