German Chancellor Angela Merkel has ruled out cancelling any of Greece’s debt, saying banks and creditors have already made substantial cuts.
But Mrs Merkel told the Die Welt newspaper she still wanted Greece to stay in the eurozone.
Greece’s left-wing Syriza party won last weekend’s election with a pledge to have half the debt written off.
Its new finance minister has refused to work with the “troika” of global institutions overseeing Greek debt.
The troika – the European Commission, European Central Bank and International Monetary Fund – had agreed a €240bn (£179bn; $270bn) bailout with the previous Greek government.
But Finance Minister Yanis Varoufakis has already begun to roll back the austerity measures the creditors had demanded as part of the deal.
Meanwhile, EU economic and financial affairs commissioner Pierre Moscovici told the BBC’s Hardtalk that Greece had to honour its previous commitments, although he said he wanted Greece to remain in the eurozone.