Chancellor Angela Merkel of Germany says it could take a decade for Europe to resolve its debt crisis.
This could be done only by countries placing legal limits on their debts, she said.
"Everyone in Europe must make an effort to achieve all that is required," Mrs Merkel said in comments posted on her website on Saturday.
The Greek crisis dominated the agenda at the G20 summit in Cannes this week.
In their final communique on Friday, G20 members said they stood ready to provide additional crisis-fighting resources to the International Monetary Fund.
The European Financial Stability Facility is to be boosted from 440 billion euros earlier this year to 1 trillion euros.
However, Mrs Merkel has confirmed that no countries outside the eurozone have offered to contribute to the EU bailout fund.
The BBC reports there is about 250 billion euros left available in the fund.
