Prime Minister Alexis Tsipras has urged Greeks to vote against the terms being offered by its creditors in the referendum this weekend, saying it would be to reject "blackmail and ultimatums".
The referendum, which takes place on Sunday, looks to be a close-run thing, with a recent poll suggesting a marginal lead for the Yes vote, at 44.8 per cent, with the No vote at 43.4 per cent.
Tsipras, who called the surprise referendum last week, has called for the Greek populace to vote against the terms of a new bailout, which he claims will give him and the negotiating team longer to secure a fairer deal.
But Eurogroup president and Dutch finance minister Jeroen Dijsselbloem has warned that Greece's creditors will not negotiate with its leaders if voters reject the terms.
Tsipras, who is expected to head up a No-vote rally ahead of Sunday's vote, urged people to back him.
The referendum will decide “whether we will accept a dead-end solution under blackmail” he said.
“I call you to say no to blackmail and ultimatums,” he said. “Decide with calm your future.”
He added: "Say No to those trying to incite panic, prevent you from making a choice - calmly and responsibly - about your future."
Either way it goes, the Council of Europe has warned the referendum will "fall short of international standards" if held as planned, citing the short notice given to voters and the lack of clarity in the question to be put to voters.