"The Greeks have done a lot. If they are not making progress it is for domestic political reasons. It is crucial that major European political parties contact their political families in Greece to convince their leaders to make a firm commitment to the EU aid package,» the economic affairs commissioner said.
"Otherwise this programme could fail and that won't help Greece or Europe,» he told the Suddeutsche Zeitung daily in an interview published on Friday.
Asked if the savings measures being demanded of Greece were too harsh, Rehn replied: «We should give the Greeks room for manoeuvre to reform their country.
"But it's important they meet their savings targets. Our experience of difficult structural reforms in Europe and elsewhere in the world is that it is better to push through quick, tough reforms than to have to pay for the mistakes of the past for a long time,» said Rehn.