BRUSSELS (AFP, REUTERS) - Greece's Prime Minister Alexis Tsipras said Wednesday his country would still hold a referendum on the terms of its bailout, urging people to vote 'No' in order to win a better deal.

In a televised address to the nation he said Greece would continue to negotiate with its international creditors, and insisted that Athens wanted to stay in Europe.

The address comes less than an hour before Eurozone finance ministers are to hold a conference call at 1530 GMT on Wednesday (11:30pm in Simgapore) to discuss the Greek issue.

"A 'No' vote does not signify a rupture with Europe, but a return to the Europe of values," he said, rebutting accusations from EU leaders that the plebiscite was essentially a vote for or against staying in the European Union.

Defying the creditors at the referendum would place them under "great pressure to continue" with negotiations, and as such it would be a "decisive step for a better deal."

Greece made a fresh reform offer to its creditors a day after defaulting on the IMF, but it was immediately rebuffed by Germany, who ruled out a deal before the Sunday referendum. Although preparations are already underway for the vote, its fate was unclear after the Council of Europe rights group said it fell short of European standards.

The letter, seen by Reuters on Wednesday, said Greece would accept terms published by the European Commission on Sunday but with a number of amendments, including maintaining a reduction on value-added tax for Greek islands and maintaining a pension supplement for the richest beneficiaries for the time being.

"There are still a lot of loose ends," one eurozone official said. "The letter mentions, for example, reform of the labour market from autumn. It's just one sentence, not more. "I don't think the Eurogroup still believes those promises just like that. By the way, they're asking for the extension of a programme which has already expired."

The letter sought an extension of the bailout which expired overnight.