MONTREAL - Jack Layton appealed Thursday to the green side of Quebecers, hoping the NDP's environmental plan to punish "big polluters" will win him more seats in the province.

Layton made the appeal as his Quebec lieutenant -- and only MP from the province -- confidently predicted the New Democrats could win up to 12 seats in a region that has traditionally given the party only a passing glance.

Layton laid out what he called a "practical" and "prudent" environmental plan in Victoria Square in front of the Montreal Climate Exchange, which allows the trading of futures contracts on greenhouse gases.

He touted the program, which promises to get tough on polluters and reward companies that clean up their acts, as the only realistic proposal.

Stephen Harper's Conservatives have no real environment plan, the NDP leader claimed before setting his sights on the Liberal's Green Shift proposal and Leader Stephane Dion, whom he's largely ignored since the beginning of the campaign.

"His carbon tax proposal is wrong, it won't work and he knows it," Layton said, the party's Quebec candidates -- some of them ecologists -- nodding their approval behind him.

"Taxing your families while letting big polluters do what they want is no solution and he knows it. It is simply -- and I quote -- 'bad policy' and he knows it."

That was a less-than-veiled reference to Dion's opposition to the notion of a carbon tax during the 2006 Liberal leadership race.

Public opinion polls consistently rank the environment among the top concerns of Quebecers and Outremont MP Thomas Mulcair said the issue is a winner for the NDP because of Dion's perceived unpopularity in the province.

The party could win between "six and 12 seats" in key ridings around Montreal and possibly Quebec City, Mulcair boasted.

He portrayed the Bloc Quebecois as a spent political force, a protest movement founded 18 years ago that has had its day.

"People are really wondering why they keep sending so many Bloc MPs back to Ottawa when they can't get anything done," he told reporters.

Quebecers "can see their values reflected in the NDP."

The NDP also unveiled a series of slick French-language television attack ads, aimed at linking Stephen Harper and the Conservatives with what are portrayed as the pro-war, anti-environment policies of U.S. President George W. Bush.

The party set aside $1 million for the Quebec ads, eclipsing the $230,000 it spent during in the province during the last campaign.

The centrepiece of the NDP leader's plan is a so-called "cap-and-trade" system to create incentives for big business to reduce their emissions.

Layton's plan includes a proposed 80 per cent reduction in greenhouse gas emissions by 2050 and a $750-million green-collar jobs fund.

He's also promising to spend roughly $1 billion a year on public transportation and an energy efficiency retrofit program, raising money through a bond program.

Layton has already promised to halt new tarsands development in Alberta until emissions are capped.