"The instalments for the IMF in June are 1.6 billion euros ($1.8 billion). This money will not be given. There isn't any to be given. This is a known fact,"

Last week, the parliamentary spokesman for Syriza said that the government would be unable to honour a repayment to the IMF

Others in the ruling party are less radical, including MEP Dimitris Papadimoulis who called on Syriza to accept "difficult compromises" in order to reach an agreement and avoid a "disastrous" breakdown in the talks.

Local media have reported that the creditors are seeking a further 5 billion euro reduction in the government's budget through measures including more pension cuts and lay-offs