Frankfurt - The European Central Bank (ECB) forecast on Thursday that Greece's public debt would peak at 161% of gross domestic product (GDP) in 2012.
Athens' debt would then decline to 127% of GDP by 2020, the ECB said in its monthly bulletin for July.
"Achieving this downward trajectory crucially hinges on the government’s willingness and ability to persevere with fiscal consolidation and implement the structural reform and privatisation programmes in full," the bank said.
A study of the sustainability of Greece's debt, currently at around €350bn, concluded that "debt dynamics largely depend on factors that are under the control of the Greek government".
Athens is in talks with the European Union and the International Monetary Fund (IMF) on a second financial rescue package worth approximately the same as one established last year, or €110bn.
Greek Prime Minister George Papandreou warned on Thursday in a German press interview that if financial aid from the EU and IMF did not come quickly, economic reforms in the debt-laden country would fail.