Banks worked urgently with the EU on a new rescue for Greece in talks in Rome on Monday, and French President Nicolas Sarkozy said a 30-year scheme to avert default was in the making.
Sarkozy declared in Paris: "We won't let Greece fall. We will defend the euro. It's in all of our interests."
Private banks, owed billions of euros by Greece, were in critical talks with EU officials through their top representative on how to restructure debt without causing a default which many say could pose severe dangers for the eurozone and global markets.
A meeting at the Italian treasury was headed by Vittorio Grilli, director general at Italy's treasury and chairman of the eurozone's economic and financial committee, and Charles Dallara, managing director of the International Institute of Finance, a forum for leading global banks.
In Paris, Sarkozy told a press conference that France was working on a 30-year scheme to give Greece time to get on top of its debt mountain.
"We have concluded that prolonging loans over 30 years, and putting them on the level of European loans indexed on Greek growth, would be a system that all countries might find useful," Sarkozy told reporters.
"We have worked very hard, the finance ministry has worked very hard with the banks and insurance companies ... on what could be a voluntary participation by the private sector," Sarkozy said.
In Berlin, Germany which is behind the pressure for private banks to bear part of the cost of a second rescue for Greece, welcomed the work by the banks and by France.
The spokesman for the German finance ministry Martin Kreienbaum said: "The German government applauds the initiatives from the private sector, as it does those coming from France."
In the next three years, Greece is due to repay about €64 billion ($90.4 billion) of debt.
Sarkozy, who holds the presidency of the G20 leading countries, said he "hoped" that fellow European Union governments would back the French plan.
Sarkozy's remarks gave substance to reports that under the embryonic scheme being negotiated in Rome, banks would roll over half of the money they should receive from maturing Greek debt into new 30-year bonds.
A further 20 percent of the money due would be reinvested in high-quality bonds, with interest being paid only at the end of the life of the loan.
Several leading figures in the European Union and eurozone have spoken in increasingly worried terms in recent days about the domino dangers of the Greek crisis.
The Greek problem is essentially in two parts. The first concerns crash budget reforms to obtain urgently needed funding under a first EU, International Monetary Fund rescue set up 12 months ago.
The second concerns talks on a second rescue, also conditional on the latest budget action on which the Greek parliament is due to vote in two days' time.
Creditors, who stand to lose money in any case, are mindful that clumsy handling of any restructuring of the debt could cause new problems.
The French plan is set against the background of how to engage private holders of Greek debt in a so-called "voluntary" rescue for Greece, otherwise threatened with bankruptcy, without causing financial markets and credit rating agencies to describe the restructuring as default.
A default rating could have wide-ranging consequences within the eurozone and even for global markets.
Another concern is that discriminatory treatment could cause an outflow of funds from Greece, and also ramp up pressure on fragile eurozone countries such as Ireland and Portugal, already the subject of rescues and possibly Spain or even Italy and Belgium.
The European Central Bank has warned that in the event of a default rating, it might cease providing lifeline funding to the Greek banking system.