Canada reaffirmed Monday that it would not sign up to fresh commitments under the Kyoto Protocol, a cornerstone of the fight against global warming.

"Canada has made clear this year that Canada will not make a commitment to a second Kyoto period," Environment Minister Peter Kent said in a briefing to Canadian journalists on the sidelines of the world climate talks in Durban.

"Our fixation, our commitment is on the Copenhagen and Cancun agreements," he said referring to accords that, in contrast to Kyoto's legally-binding curbs on greenhouse gases, favour a voluntary approach.

"We believe ultimately a new agreement that includes all of the world's major emitters in both the developing and developed world is the only way to materially reduce annual megatonnage to the point that we can work to prevent global warming achieving or exceeding two (degrees)."

The goal set by a core of countries at the stormy Copenhagen Summit in 2009, and supported at last year's climate conference in Cancun, Mexico, sets a goal of limiting warming to two degrees Celsius (3.6 degrees Fahrenheit).

But developing countries and green campaigners say the voluntary approach initiated at Copenhagen will fall far short of what is needed to curb the surge in heat-trapping carbon gases.

The UN Framework Convention on Climate Change (UNFCCC) gathers 194 countries under a process launched under the 1992 Rio Summit.

Tension at this year's round of talks, running in Durban until Friday, is running high over the fate of Kyoto, the only global accord that specifies curbs in greenhouse gases.

Current pledges by rich countries under Kyoto expire at the end of 2012.

Several key nations beside Canada, including Japan and Russia, have said they will not renew their vows.

They say a second commitment period is senseless so long as emerging giants and the United States, which has refused to ratify Kyoto, are not bound by the treaty's constraints.

Rumours spread at the Durban conference on Monday that Kent had announced Canada was formally abandoning Kyoto, but this resulted from a mistaken news report, according to journalists who attended the briefing.

Last month, the Canadian broadcaster CTV cited unnamed sources saying Ottawa would give official notice in December that it would withdraw from the Protocol.

In diplomatic terms, that move would be far more significant than not signing up to a new roster of pledges, for it would make Canada the first country to abandon the landmark pact.

The United States signed Kyoto as a framework agreement in 1997 but declared in 2001 that it would not ratify it, saying it was too costly and unfair.

Canada agreed under the Kyoto Protocol to reduce CO2 emissions to 6.0 percent below 1990 levels by 2012, but its emissions have instead increased sharply. Pulling out of Kyoto would allow Canada to avoid paying penalties for missing its targets.