In an interview with Japan's Asahi newspaper published on Thursday, Zoellick said the fund would likely be finalised at the Group of Eight summit to be held on Japan's northern island of Hokkaido on July 7-9.

"(The fund) will be an important contribution because the climate change issue is one where we need to support U.N. negotiations (on a framework to succeed the Kyoto Protocol)," Zoellick said. Quoting unspecified sources, Asahi said more than 10 countries were expected to set aside about $5.5 billion for the fund.

Environment ministers from the G8 rich nations agreed earlier this week that ensuring funds to help developing countries adapt to climate change and cut greenhouse gas emissions was vital. Tokyo and Washington called on other donor countries to join a fund they want to set up.

Apart from the United States, Britain and Japan, Zoellick was quoted as saying that he would expect Australia, Canada and some European countries to take part in the scheme.

"I can't say today exact sums or exact countries, but the signs are getting positive," Zoellick was quoted as saying.

The United States and Britain pledged to contribute $2 billion and 800 million pounds respectively, Asahi reported. Tokyo was expected to contribute more than 100 billion yen, it added.

The United States, Britain and Japan expect the new financing mechanism to encourage developing countries such as India and China to take part in U.N. negotiations on the post-Kyoto Protocol framework, Asahi reported.

About 190 nations have agreed to negotiate by the end of 2009 a successor treaty to the Kyoto Protocol, which binds 37 advanced nations to cut emissions by an average of 5 percent below 1990 levels by 2008-12.

But wide gaps exist inside the G8 and between rich and poorer nations over how to share the burden for fighting the climate change that causes droughts, rising seas and more severe storms.