Greek Prime Minister Antonis Samaras faces a week of wrangling as his coalition government tries to find common ground on two more years of austerity to persuade international lenders to keep the country in the euro.

Inspectors from the European Commission, European Central Bank and International Monetary Fund, known as the troika, are due back in Athens on Sept. 7 to complete a review begun in July. They are likely to find that the three coalition partners are still working on an 11.5 billion-euro ($14.5 billion) blueprint that may test the cohesion of Samaras's government.

"Implementation is key in Greece, which means the key is whether the government survives to implement the program," said Athanasios Vamvakidis, head European currency strategist at Bank of America Corp. in London. "Greece just got a new aid package, a large haircut and a new government, and still needs more money. If Greece cannot implement the program now, the troika is likely to conclude that it is pointless funding Greece."