OTTAWA and TORONTO -- The federal Conservatives may have picked another fight with Canada's largest industry, as the party's environment critic vowed yesterday that a Tory government would implement mandatory fuel efficiency standards in cars.

Bob Mills, the Conservatives' environment critic, said yesterday the party would push the auto industry and the provinces, which enforce many of Canada's environmental regulations, to cut national fuel consumption 25 per cent by 2010. That would be done by requiring auto makers to produce more efficient cars, a goal that the industry prefers to achieve voluntarily.

"We've got to change with the times," he said in an interview.

He described his position on mandatory fuel efficiency as party policy and documented the position in an election questionnaire he filled out for the Sierra Club of Canada. He said the position is part of a 50-year plan for achieving environmental sustainability that has been approved by the party's caucus.

There is no specific reference to fuel efficiency standards in the party's election platform, although its plan for the environment includes a national strategy for more energy conservation and alternative sources of fuel.

The Liberals, which have dominated the auto industry ridings of Southern Ontario during the past three federal elections, have agreed with the industry's view that fuel efficiency should be achieved through voluntary targets.

In filling out the Sierra Club's questionnaire, the Liberals said they're committed to fuel efficiency improvements but stopped short of supporting mandatory guidelines. The other three major parties -- the New Democrats, the Bloc Québécois and the Greens -- all supported the proposal to implement new standards.

The 25-per-cent target, however, is the same requirement the Liberal government is insisting on as part of the Kyoto Protocol, an international treaty on global warming that Conservative Leader Stephen Harper has said he would scrap. Mr. Mills repeated his position yesterday that he doesn't like Kyoto either.

Elizabeth May, executive director of the Sierra Club of Canada, said the Conservatives' answer to the question about mandatory fuel economy standards was the most pleasant surprise among all of the parties' answers to the group's 13-part questionnaire.

"Having the Conservatives come down on the side of regulating the auto industry is really quite strong."

Mr. Mills, whose Red Deer, Alta., riding is dominated by the oil industry, said California is on the path to more aggressive fuel emission standards, so it's inevitable that the rest of the continent will soon follow suit. "That's where we're going, whether we like it or not."

California, the most populous of the American states, unveiled a proposal this month to cut emissions of carbon dioxide and other gases linked to global warming as much as 30 per cent over the next decade. The proposal is expected to be challenged in court by the auto industry.

But Mr. Mills said he would work with the provinces and the industry to bring in the changes. "I think it's a no-brainer to support the environment, and industry supports that."

Industry officials said yesterday, however, that the Conservatives' goal is unrealistic.

"We're going to continue to have our discussions with the government," said Mark Nantais, president of the Canadian Vehicle Manufacturers Association, a lobby group for DaimlerChrysler Canada Inc., Ford Motor Co. of Canada Ltd. and General Motors of Canada Ltd. Those discussions, so far, have essentially involved auto makers telling Ottawa that reducing fuel consumption by 25 per cent by 2010 can't be done.

Mr. Nantais said yesterday that the numbers show it can't be done.

About 8 per cent of the vehicle fleet is replaced every year and about 1 per cent of those vehicles have the latest technology and other advances that help reduce fuel consumption.

Jim Miller, vice-president of corporate affairs for Honda Canada Inc., said one key difficulty is pinpointing the starting point for the reduction. "A 25-per-cent improvement in fuel efficiency from what level?"

The Liberal government made the target clear, he said, but it never said that the 25-per-cent improvement was from 2001 levels or 1999 levels or any particular year.

The Conservatives' stand on mandatory fuel efficiency standards marks the second time in less than a month that the party has butted heads with the powerful auto industry. This month, the Conservatives also raised the industry's ire when the party's platform stated that it would eliminate subsidies and other "corporate welfare."

It has become standard procedure for many auto makers to land hundreds of millions of dollars from taxpayers when they set up a new plant, or sometimes even when they only make improvements to existing facilities.

The Conservatives are generally viewed by environmental groups as being the least sympathetic to their cause, although Mr. Mills said his party would take solid steps to preserve the environment. The self-described environmentalist said the Liberals have done more talking than anything else.

During a debate on the environment in Ottawa on Monday, Mr. Mills, his party's representative at the event, was heavily criticized by the other panelists.

Environment Minister David Anderson said the Conservative Party is the only major party that is out of step with Canadians on environmental issues.

The new Conservative Party hasn't yet held an inaugural convention, so none of its positions -- including the platform -- have received the ratification by party members that would make them official party policy.

Opinion polls suggest the Conservatives are in a dogfight with the incumbent Liberals to form the next government.