Together with at least €10 billion expected from the International Monetary Fund in the first year, it could add up to the biggest multilateral financial rescue ever attempted.

"With today's decision, Europe sends a very clear message that no one, any longer, can play with our common currency, no one can play with our common fate," Greece's Prime Minister George Papandreou said in a statement.

In a rare weekend telephone conference, finance ministers of the 16 member nations backed a detailed plan for Greece to borrow from euro-zone governments and the IMF at significantly below market rates.

IMF chief, Dominique Strauss-Kahn, said the IMF was ready to provide help, possibly through a multi-year standby loan arrangement, and would hold talks with Greek, EU and European Central Bank officials in Brussels on April 12.

A Greek Finance Ministry official said it was logical to expect the package would amount to significantly more than €40 billion over 3 years.