The G20 is committed to an "ambitious outcome" at December's UN climate change summit in Copenhagen, it said in a communique after talks Saturday, but did not agree a figure for climate finance.

"We committed to take action to tackle the threat of climate change and work towards an ambitious outcome in Copenhagen," the group of leading economic powers said.

"We discussed climate change financing options and recognised the need to increase significantly and urgently the scale and predictability of finance to implement an ambitious international agreement."