Funding from rich nations to the developing world has emerged as the main stumbling block to progress in climate negotiations ahead of international talks in Copenhagen in December.

Ethiopia warned last week that Africa would veto any deal at Copenhagen that was not generous enough.

The 27-country EU is trying to find unity on its contribution to break the impasse.

"A deal on financing will be central to achieving an agreement at Copenhagen," said a draft European Commission report obtained by Reuters on Tuesday.