Financier George Soros unveiled a plan Thursday at the UN climate talks to free up to 100 billion dollars (68 billion euros) for poor countries to combat climate change and cope with its impacts.

The funds could be made available immediately, and not add to the national deficit of donor countries, he said.

"Developed countries' governments are laboring under the misapprehension that funding has to come from their national budgets but that is not the case, they have it already," Soros told journalists.

"It is lying idle in their reserves accounts and in the vaults of the International Monetary Fund (IMF)."

How much rich nations -- who acknowledge a historical responsibility for global warming -- should give developing ones, and the source of those funds, are among the most contentious issues dividing the crunch climate summit underway in Copenhagen.

Consensus is forming around the release of a "fast-start" fund of 30 billion dollars to cover the period 2010-2012, but needs are set to escalate into the hundreds of billions within a decade.

In September 2009, the IMF distributed to its members nearly 300 billion dollars worth of a financial instrument called Special Drawing Rights (SDRs).

More than half of that fund went to the world's 15 biggest developed economies, where they have remained largely untouched in reserve accounts.

"I propose that the developed countries... should band together and lend 100 billion dollars worth of these SDRs for 25 years to a special green fund serving the developing world," Soros said.

The money could be invested in low-carbon energy sources, reforestation, rain forest protection and programmes to adapt to drought, floods and other consequences of climate change, he said.

Under the plan, the IMF would use gold reserves to cover the interest costs on the SDRs lent by rich countries.

"This is a simple and practical idea, and there is a precedent for it," Soros said, noting that Britain and France each recently lent two billion dollars' worth of SDRs to a special fund for loans to poor countries.

Member states could use the IMF's gold reserves -- currently 100 million ounces -- to guarantee payment of the interest, and the repayment of the principal, Soros said.

"Soros' proposal shows exactly the kind of ambition and urgency we need to see from rich country governments themselves," commented Robert Bailey, Oxfam International's senior climate advisor.