Representatives of the creditors that are keeping Greece economically afloat -- the European Central bank, the European Commission and the International Monetary Fund, together known as the Troika -- are set to arrive in Athens Tuesday to appraise Greece's progress in implementing austerity measures required to continue to receive bailout money.

Questions loom over whether the country will be able to make a €3.2 billion ($3.9 billion) bond payment due Aug. 20.

A default by Greece would hit global markets hard and would almost certainly herald the country's exit from the euro zone, which would have serious ramifications for global economic recovery. Markets won't have to wait long to find out whether or not Greece can pay its bills.

The moment of truth is July 26th, when Finance Minister (Yannis) Stournaras has to present the new austerity package to the EU, IMF and the ECB, said David Rosenberg, chief economist for Gluskin Sheff + Associates Inc. (Toronto: GS), in his Monday note.

Tuesday's meeting will determine how the IMF decides on the next financial disbursement to Greece, which has received €240 billion in rescue funds since 2010.

Greece is unlikely to receive any further bailout loan tranches until at least September, said a note from Capital Economics on Monday.

Payments from the second rescue package, valued at up to €100 billion out of a total bailout fund of €173 billion, have been snagged by Greece's failure to meet fiscal and structural reform targets that were established in March. It has already received about €40 billion of the second round of bailouts.

The Greek coalition has been unable to agree on €11.5 billion in spending cuts to meet austerity requirements. If it doesn't meet these terms, the European bailout funds will be further tapped for Greece, leaving less for Spain and Italy.

We are proceeding with the mergers in the public sector and we are going to find all of the cutbacks demanded, or in some cases propose equivalent measures worth more than twice what the troika is asking, a top Greek government official told the Wall Street Journal.

The Troika is expected to demand a further $2 billion in cuts. So far Greece has been unable to come up with about a third of the cuts already expected.

In August, Prime Minister Antonis Samaras is expected to ask for a two-year extension on the austerity targets. On Sunday he told former U.S. President Bill Clinton, who was in Athens on a trade-promotion tour that Greece was in its version of the 1930s Great Depression.