"Before the end of the year, the Canadian parliament will be asked to vote on the ratification of the Kyoto accord," Chretien told the World Summit on Sustainable Development (WSSD).

The move surprised and delighted environmentalists as Canada has often worked closely with the United States on global environmental issues.

"It has split the North American bloc on Kyoto. Canada has joined the rest of the world and left the United States behind," said Jennifer Morgan of WWF.

Steven Guilbeault, a Canadian WWF campaigner, said he expected parliament to approve the pact. "If there was a vote tomorrow morning it would go through," he said.

One hundred Liberals and the Bloc Quebecois, the New Democratic Party, have said they supported Kyoto, he said.

U.S. President George W. Bush threw the pact into doubt when he pulled out of the Kyoto treaty last year.

To come into force, Kyoto must be ratified by developed countries responsible for 55 percent of 1990 carbon dioxide emissions. The United States emitted one third of that total.

But since the U.S. pullout, momentum has gathered to push ahead, with the European Union leading diplomatic efforts to keep the pact alive.

If it ratifies the pact, Canada will have until 2012 to cut emissions from power generation, transport and other sectors by six percent from 1990 levels. Latest estimates show Canada's emissions had risen 20 percent by 2000.

The U.S. position is that Kyoto would harm its economy, but it has said it would not try to prevent others from going ahead.

"The U.S. position is we are not trying to discourage other countries from ratifying the Kyoto Protocol," Robert Card, undersecretary at the U.S. department of energy told Reuters on the sidelines of the WSSD.

Russian President Vladimir Putin has indicated he wants the State Duma parliament to ratify Kyoto after the summer.