Greece must stick to the deal agreed with its international backers and enact promised reforms to remain within the euro zone, says German Finance Minister Wolfgang Schaeuble.
Greece is due to receive a €5.2 billion tranche of bail-out loans tomorrow although news agency reports suggested €1 billion may be delayed.
This is despite rising uncertainty over the country's political future, the European Commission said.
The Greeks need "to form a stable government and strictly respect their commitments, in the same way that we will respect our obligations to Greece" according to the German Finance Minister.
"If Greece wants to remain in the euro zone, there is no better solution than the path it has already taken," Schaeuble said, referring to austerity cuts and reforms in return for a €240 billion debt bailout.
"You can't have one without the other," he added.
"The payout will take place because it has already been approved," Amadeu Altafaj, a spokesman for European Union economy commissioner Olli Rehn, told AFP today.
"The payout will take place because it has already been approved," Amadeu Altafaj, spokesman for European Union economy commissioner Olli Rehn, told AFP today.
Athens was also warned by Luxembourg on future loans as Foreign Minister Jean Asselborn said that money would not be forthcoming unless Greece installed a stable government.
"We have to say to the Greek people right now that the situation is serious, that no European Union country will be able to release even a portion of the €130 billion for the Greeks, if there is no functioning government that respects the rules and manages the disbursed money," he said in Brussels.
Euro zone finance ministers are due to meet on Monday in Brussels.
The leader of the Greek radical left-wing Syriza party charged with forming a government, Alexis Tsipras, planned to write today to the highly indebted nation's overseas lenders that Athens would renege on its austerity commitments.
In Athens, Gikas Hardouvelis, economic advisor to outgoing Prime Minister Lucas Papademos, warned that Greece's future was up in the air after voters in Sunday elections deserted the mainstream parties which have endorsed tough EU and International Monetary Fund bail-out conditions.
"If we say no to everything, we leave the euro zone," Hardouvelis said.
Greece is due to repay on May 15 around €450m of bonds that holders refused to write down under a restructuring of private debt. Athens is also scheduled to return some €3.3 billion to the European Central Bank by May 18.
Merkel reiterates treaty stance
The German Chancellor Angela Merkel reiterated today that EU countries that have signed the bloc's fiscal pact for greater budgetary discipline must stick to what they have agreed.
"Everyone must stick to the things we have agreed. Twenty-five countries have already signed the fiscal pact," Merkel told reporters as the pact comes under increasing pressure, with French president-elect Francois Hollande seeking its renegotiation.
The German government is urging both houses of parliament to vote on the permanent euro zone bail-out fund and new rules on budget discipline before the summer recess, according to a spokesman for the Chancellor.
Earlier a source in the ruling centre-right coalition was reported as saying that the parliament will not vote until at least mid-June on the European Stability Mechanism and the so-called fiscal compact, casting doubt over the fund's planned start date of July 1.
Monti calls for growth
Italian Prime Minister Mario Monti called today for a "coalition of the willing" in the EU for promoting growth ahead of key talks in Brussels later this month.
"I have promoted a roundtable of the European Council, a coalition of the willing, maybe of the slightly unaware willing," with concrete proposals for boosting growth, Monti said at a conference in Florence.
