A senior member of Chancellor Angela Merkel's party issued a stark warning to Greece on Monday, August 13 saying Germany would not hesitate to veto further aid to the country if there were any signs it was not meeting the conditions of its bailout, Reuters reported.

The comments, by the deputy parliamentary leader of Merkel's Christian Democrats (CDU) Michael Fuchs, are a sign that frustration with Greeceamong ruling party lawmakers is nearing the breaking point.

The "troika" of the European Commission, the European Central Bank and the International Monetary Fund is due to decide on the disbursement of the next tranche of money from Greece's 130 billion euro bailout package in September.

"Even if the glass is half full, that won't be sufficient for a new aid package. Germany cannot and will not agree to that," Michael Fuchs said.

"We long ago reached the point where the Greeks must show they are capable of delivering a shift. A policy of the last, last, last chance won't work anymore and must come to an end."

Merkel has suggested in the past that cutting off aid to Athens, a step which would likely push it out of the euro zone, carries too many risks for the bloc.