Fresh from his Peace Prize ceremony in Oslo, Norway the former US vice-president was due here with less than two days left of talks to reach a framework deal on action after the Kyoto Protocol's commitments end in 2012.

The United States and several other countries are fighting EU-led calls to mention specific goals for slashing carbon emissions after 2012.

Negotiations are also stalled on key areas as to how to help developing countries fight climate change.

Gore, who has turned into a tireless green activist since he narrowly lost the race for the White House to George W. Bush in 2000, voiced concern as he headed to the marathon UN conference on the Indonesian resort island.

"Some of the reports are worrisome. But I know from experience in previous such meetings that breakthroughs, when they do occur, usually happen in the last 48 hours, sometimes in the last four to eight hours," Gore said late Wednesday in Stockholm.

"And hope springs eternal," he added.

Gore shared the Nobel Peace Prize with the Intergovernmental Panel on Climate Change (IPCC), the top UN climate panel which has warned of catastrophic consequences if global temperatures keep rising.

Bush has rejected the Kyoto Protocol, arguing that it is too costly and unfair as fast-growing emerging economies are under no obligation to slash carbon emissions.

Australian Prime Minister Kevin Rudd, in Bali on his first foreign trip in office, ratified the Kyoto Protocol as the first act of his new government, leaving the United States as the only major industrial nation to reject the treaty.

Hans Verolme, director of the WWF conservation group's Global Climate Change Programme, said that Bali must lead to a deal by 2009 under which all rich countries make deep cuts in emissions.

"Ministers need to see the wood from the trees and personally invest in a political package that meets the needs of a climate-stressed world," he said.

The United States, supported notably by Japan, Canada and Russia, does not want the Bali talks to specify a numerical target for cutting emissions after 2012.

"We are at a defining moment. We must develop a global response that rises to the scale and scope of the challenge before us," US Under-Secretary of State Paula Dobriansky said.

"A post-2012 arrangement must be environmentally effective," she said. "It must also be flexible to attract global participation."

The European Union wants to include a reference by industrialised countries that names a cut of 25-40 percent in their emissions by 2020, compared with 1990 levels.

"We'd prefer it to stay in, there's no question of that," said Hilary Benn, Britain's secretary of state for environment. "It reflects what the IPCC says."

Ministers are also divided over the deadline for the next deal.

A 2009 deadline is favoured by some while others argue that a later date would give the chance for the next US president to settle in and maybe coax the world's top greenhouse emitter into the Kyoto format.

Developing countries are meanwhile pushing for support from rich nations to encourage conservation of their forests and transfer of clean technology.

Pakistan's Munir Akram, representing a group of 77 developing nations, said Wednesday that talks on the technology transfer broke down in the early hours of the previous night.

He said the row came down to only a single word and hinted that the United States was one of the nations behind the disagreement.

"I think our partners insisted on using the word 'programme' and our group insisted on using the word 'facility,'" said Akram, Pakistan's ambassador to the United Nations.

He said he was hopeful of solving the dispute but urged developed countries to set and pursue clear targets on cutting their gas emissions.

"This is just an example that at a certain level, the negotiators of our partners don't seem to live up to the rhetoric that we are hearing about their desire for the maximum Bali outcome," he said.