Time was running out for a global climate deal as crunch UN talks entered their final week on Monday with an apparent concession from top polluter China.
Ahead of a closing summit to be attended by about 120 leaders, Australia warned that the talks could be staring at failure as ministers prepared to meet behind closed doors to try to hammer out a draft pact.
After insisting that rich nations must cough up far more money to seal a deal, China said it no longer expected them to underwrite its own efforts to fight climate change.
China's top climate negotiator, vice foreign minister He Yafei, told the Financial Times: "China will not be an obstacle (to a deal).
"I know people will say if there is no deal that China is to blame. This is a trick played by the developed countries. They have to look at their own position and can't use China as an excuse."
China and the United States, the world's two largest carbon polluters, have clashed on key issues such as how to share the burden of slashing greenhouse gases and whether the rich world owes developing countries a "climate debt".
"Financial resources for the efforts of developing countries (to combat climate change are) a legal obligation," He Yafei told the newspaper in an interview in the Danish capital.
"That does not mean China will take a share -- probably not... We do not expect money will flow from the US, UK (and others) to China."
China has vowed to reduce its carbon emissions per unit of gross domestic product by 40 to 45 percent by 2020. But experts say that given economic growth projections, its emissions could still double.
Australian Prime Minister Kevin Rudd, who is due to attend the summit with other leaders including US President Barack Obama, said reaching a consensus looked hard.
"There's a big risk that we will have conflicting views between developed and developing countries," Rudd said. "And there is always a risk of failure here."
Rudd, who will act as a deal-brokering "friend of the chair" in Copenhagen, said it would be difficult to find a middle ground given the starkly opposing positions carved out by developed and developing nations.
"We've got a lot of work ahead of us," Rudd told Sky News, calling for "more compromise all round".
About 50 environment ministers from the 194-member United Nations Framework Convention on Climate Change gathered informally for their first major get-together of the talks on Sunday as the 12-day marathon took a day off.
The gathering's daunting goal is to tame greenhouse gases -- the invisible by-product derived mainly from the burning of coal, oil and gas that traps the Sun's heat and warms the atmosphere.
Meeting under the chairmanship of former Danish minister Connie Hedegaard, the ministers are tasked with turning a problem-plagued blueprint into a landmark deal on climate change that can be endorsed by the leaders on Friday.
But in their first week, negotiators made scant progress on any of the major issues, stoking fears that the outcome would be a poor fudge.
Scientists say that without dramatic action within the next decade, Earth will be on course for warming that will inflict drought, flood, storms and rising sea levels, translating into hunger and misery for many millions.
If all goes well, the conference will agree an outline deal of national pledges to curb carbon emissions and set up a mechanism to provide billions of dollars in help for poor countries in the firing line of climate change.
French Ecology Minister Jean-Louis Borloo said there was a widespread desire to prevent the summit ending in stalemate.
"We don't want to end up one day regretting that we had an extraordinary opportunity but allowed fear to win the day," he said.