But they are reluctant to promise any dates for completing negotiations. Businesses also want early clarification to guide long-term investments, for instance in solar or wind power.

"We think it will take several years," a senior Canadian official said of the process to renew Kyoto, which obliges about 40 industrial nation to cut emissions of greenhouse gases by 5.2 percent below 1990 levels by 2008-12.

"The real target is to have a new phase in place by Jan. 1, 2013," said the official, who could not be named because of the current Canadian election campaign.

Kyoto is a first step toward reining in heat-trapping gases from burning fossil fuels in factories, power plants and autos blamed for warming the planet.

Canada hopes the Nov. 28-Dec. 9 meeting will launch twin sets of talks - one between Kyoto backers and a wider set to see how far outsiders such as the United States and developing countries might join a UN-led fight against warming.

Environmentalists say that agreement on a successor to Kyoto by 2008 is essential, partly to reassure investors in fledgling markets for trading carbon dioxide, the main greenhouse gas, that their commodity will continue to have a price.

WORRIED BY EU

"Many of us are extremely worried by the position of the European Union," said Tony Juniper of Friends of the Earth, who accused the EU of failing to do enough to push for a deadline. "The end date for talks should be set for 2008."

"We're negotiating," Sarah Hendry, head of the British delegation which holds the EU's rotating presidency, told a news conference when asked if the EU was pushing for a deadline.

She said the Montreal meeting had either to set an end date for the Kyoto talks or send a strong signal of intent to investors that Kyoto would be extended beyond 2012.

One European delegate said the EU seemed reluctant to commit to an early deadline partly because US President George W. Bush, who opposes Kyoto, will step down in 2009.

A new president might be more willing to join UN schemes to rein in global warming. Bush pulled the United States out of Kyoto in 2001, saying it wrongly excluded developing nations and would cost American jobs.

Environmentalists also accused Japan of trying too hard to force developing countries to promise to brake their emissions as part of a final package.