COPENHAGEN, Denmark - The specter of failure loomed at the UN climate summit Monday as an African negotiator said the talks were at "code red" while China accused wealthy nations of trickery.

While environment ministers haggled behind closed doors, some of the biggest players gave a glimpse of the rift to be bridged between rich and poor nations when some 120 leaders gather for the climax on Friday.

Australian Prime Minister Kevin Rudd, whose country is the industrialised world's biggest per-capita polluter, fretted over the possibility of failure without compromise all round.

"There's a big risk that we will have conflicting views between developed and developing countries," Rudd said in Australia. "And there is always a risk of failure here."

Rudd said it would be difficult to reach a "consensus up the middle" given the often opposed and entrenched positions of developed and developing nations.

"We've got a lot of work ahead of us," he told Sky News television.

Asked if there had been any movement on the major issues, one of the two co-chairs of the talks, Michael Zammit Cutajar, told AFP: "No."

A top Western negotiator, speaking on condition of anonymity, said a round-table session between around 50 environment ministers Sunday had been soured by "growing tensions between the Americans and Chinese," saying delegates had merely repeated their previous stances rather than giving ground.

"At the back of everyone's mind is the fear of a repeat of the awful scenario in The Hague," she told AFP, referring to a climate conference in 2000 on completing the rulebook for the Kyoto Protocol that broke up angrily without agreement.

In an apparent concession, China said it might not take a share of any Western funding for emerging nations to fight climate change.

But in a pointer to the tensions backstage, Vice Foreign Minister He Yafei said China would not be the fall guy if there were a fiasco.

"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," he told the Financial Times.

Britain's climate minister, Ed Miliband, urged negotiators to work faster to break the deadlock.

"There are still issues of substance and process to be overcome in the coming days," he told a press conference.

"Leaders are practically on their way ... Leaders always have a very important role in this. But frankly it's also up to negotiators and ministers not to leave everything up to the leaders, but to get our act together."

Asked about the state of negotiations, Nigeria's pointman rang the alarm bell.

"It is 'climate code red' right now, we are in code red right now, we stand at the crossroads of either hope for Africa or hope dashed in 'Hopenhagen'," Victor Ayodeji Fodeke told AFP.

Campaigners were equally blunt, with Greenpeace saying the summit had five days "to avert climate chaos" and that a legally binding outcome was vital for the survival of millions of people.

The organisation said that emissions targets so far offered by Western leaders such as US President Barack Obama amounted to "peanuts".

Jeremy Hobbs, head of Oxfam, said the negotiations were stuck.

"Rich countries won't budge on climate cash or emissions targets and the big players don't want to talk about the kind of deal that will come out at the end of the week," he said.

"All countries will need to give a little ... We have a golden opportunity to avert climate disaster. It must not be wasted."

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.

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.