The European Union's financial affairs chief Pierre Moscovici told German radio on Friday, just before a Bundestag vote on a bailout extension for Greece, that allowing any country to leave the euro zone would simply raise the question "who's next?".

"If a country, any country, leaves, the question will arise: who is leaving next?" the European Commissioner for Economic and Financial Affairs told Deutschlandfunk in an interview.

But he added that Greece had to meet its international commitments and ensure that any additional spending resulting from its economic policies were financed.

"The reforms the Greek government wants to launch must be financed. It is not time to talk about debts. We'll talk about that at the right time. But it's important for me to say that this is not about a reduction of debt - there's no haircut."