Eurozone leaders are toying with the idea of asking China and other emerging powers to help them out of the debt crisis by taking part in a bailout fund, but some are reluctant to call in Beijing.

The possibility of asking for China, Brazil and others to come to their rescue emerged at a summit on Sunday as European leaders scrambled to find ways to boost their defences against the crisis.

The eurozone wants to beef up its 440-billion-euro rescue fund, the European Financial Stability Facility, to convince markets it has the means to protect highly indebted nations such as Italy.

"A quite broad agreement is taking shape on the reinforcement of the EFSF," French President Nicolas Sarkozy told reporters, cautioning that long hours of negotiations remained ahead in another EU summit set for Wednesday.

German Chancellor Angela Merkel said "two models" were on the table while EU president Herman Van Rompuy said the two could be combined to provide a "cumulative effect."

While they did not provide details, several sources familiar with the talks said negotiations were difficult.

Eurozone leaders are trying to increase the EFSF's firepower without increasing the guarantees each state provides to the fund -- a sensitive issue for richer northern nations such as Germany, which are tired of bailing out weaker ones.

One option, according to EU sources, would see the EFSF act as an insurer on part of the debt issued by countries deemed at risk in order to keep investors interested in their bonds. Germany appears to have convinced France to drop its opposition to this idea.

The second option calls for the creation of a second fund attached to the EFSF to garner contributions from nations outside the EU. This is where eurozone leaders disagree.

"The Chinese have said they are interested, but some (eurozone) member states are sceptical at the idea of having a Chinese contribution to the EFSF," said a European diplomat.

A source close to discussions on the matter said the fund would be a "special purpose vehicle" to attract strong investors such as "emerging nations, sovereign funds and private investors."

Their capital and guarantees would be used to raise money in the markets and then buy the debt of weak eurozone nations. In return, the EFSF would promise to shoulder any losses in case a nation defaults.

To circumvent fears on a role for China in the EFSF, eurozone negotiators are working on the possibility of the "vehicle" being attached to the International Monetary Fund.

The so-called BRICS group - Brazil, Russia, India, China and South Africa - has voiced willingness to help Europe overcome its debt crisis amid concerns it could spark a new global recession.

The emerging powers, Europeans, and the United States, will hold a key G20 summit on November 3-4 hosted in Cannes, southern France.

They will discuss whether to increase the IMF's resources to combat the eurozone crisis, which emerging nations support but the United States opposes.