Europe's leaders are gearing up for a high-stakes week of financial diplomacy that could determine Greece's future and the stability of the 17 countries that use the euro.

The first round of shuttle diplomacy began today with Germany's Foreign Minister, Guido Westerwelle, hosting his Greek counterpart, Dimitris Avramopoulos.

This comes ahead of a meeting in Berlin on Friday between their countries' leaders, Chancellor Angela Merkel and new Greek Prime Minister Antonis Samaras.

Mr Westerwelle, speaking alongside Mr Avramopoulos after their talks, said Greece needs to carry out the reforms that have already been agreed upon, and insisted anew that "a substantial softening of the agreements and the agreed reforms is not possible from the German government's point of view."

He added that Germany "wants us to remain together in the euro zone" but that "the key to success lies in Athens."

The euro zone is awaiting a report, expected next month, on Greece's progress in implementing reforms and austerity measures demanded in exchange for two massive bailout packages.

The report is being compiled by the so-called "troika" - representatives of the European Union, European Central Bank and International Monetary Fund.

Neither Mr Westerwelle nor Mr Avramopoulos would be drawn on whether Greece can or should get more time to fulfil its austerity and reform targets, insisting that they would wait for the troika report.

French President Francois Hollande visits Berlin on Thursday for discussions with Merkel and then will meet Samaras in Paris on Saturday.

Jean-Claude Juncker, the Luxembourg prime minister who chairs the eurozone finance ministers' meetings, is due in Athens Wednesday.

Meanwhile, Greece's finance officials were working to hammer out €11.5 billion in spending cuts necessary for it to continue receiving the international funding that is protecting it from bankruptcy.