Rich countries are under pressure to kick in 10 billion dollars a year in "fast-track" funding from 2010 to 2012.

Further negotiations would be needed over the next year to flesh out the agreement. Once ratified, the accord would take effect from 2013.

Delegates said the next few days would see countries lay out their positions before some 110 world leaders -- including US President Barack Obama, Premier Wen Jiabao of China and Indian Prime Minister Manmohan Singh -- arrive for the climax.

But an earlier proposed paper by conference chair Denmark, dated November 27, that leaked at the conference on Tuesday was savaged by greens and aid activists.

They said it was too favourable to rich countries on emissions curbs and money and worried that it failed to show support for the UNFCCC's Kyoto Protocol, the landmark treaty shunned by the United States.

"Like ants in a room full of elephants poor countries are at risk of being squeezed out of the climate talks in Copenhagen," said Antonio Hill of Oxfam International.

A delegate from a major European nation, questioned by AFP, said he was unbothered by the leaked draft.

"It's already out of date," he said.

Climate change is already forcing people from their homes, according to a report released Tuesday by the UN's International Organisation for Migration (IOM). Most move within their countries or to a neighbouring state.

"Large-scale human movement from climate change and environmental degradation is not only inevitable but is already happening," IOM said.

The UN refugee agency has estimated that some 24 million people worldwide have fled their homes due to environmental factors.