A Greek debt relief scenario that put back interest payments until 2048 would mean the nation's eurozone creditors deferring receipt of up to 123 billion euros, according to a forecast by Germany's Finance Ministry.
The ministry's calculations, which were contained in a letter to a member of parliament seen by Reuters on Friday, contemplated the various restructuring scenarios laid out by the eurozone bailout fund, the European Stability Mechanism (ESM).
"With such an interest deferral, it would de facto be a new loan with a volume that depends on the development of interest rates," the document said. "The estimated volume of the deferred interest up until 2048 would be around 118-123 billion euros."
The Finance Ministry declined to comment specifically on the paper.
The International Monetary Fund (IMF) says it cannot contribute loans to Greece's current bailout unless it gets assurances that its debt will be sustainable.
The Fund has estimated that the Greek economy will only grew by 1 percent per year on average and that Greece will return to a primary surplus of 1.5 percent from 2023 after five years at 3.5 percent.
Greece needs about 7 billion euros in loans from its 86-billion euro rescue package to repay debt maturing in July, but the disbursement hinges on its lenders' assessment of its bailout progress, the conclusion of the so-called second review.