TORONTO - With the finish line in sight, Justin Trudeau took his Liberal leadership bid to the financial heartland Wednesday, accusing both Prime Minister Stephen Harper and NDP Leader Tom Mulcair of pandering to political extremism.

At the same time, Trudeau declared he would "not go negative" in any election campaign if he becomes party leader.

"We have two parties that are ideologically based around the fringes," Trudeau said. "Where the Liberal party needs to be focused on is the actual large mass of Canadians ... who are not driven by a specific polarizing issue."

Speaking to business leaders at a downtown hotel, Trudeau said part of him was impressed how Harper won a majority government by using a high level of control, dominance, aggression and strategic divisions.

"I know that it doesn't represent what Canada is," he said.

Mulcair, he said, had adopted Harper's divisive approach by attacking the resource economy of the West to pander to progressives in the East, while "playing extremely dangerous games with soft nationalists and sovereigntists" in Quebec.

"I am reminded of why it is so important that the Liberal party exists: that we remain a pragmatic, values-based alternative — a government or a party that is not going to be wrapped up in a particular ideology of the left or the right," he said.

Trudeau also assailed the government's single-minded focus on economics at the expense of the environment, saying it should not be an either-or proposition. "The economy is too important to neglect the environment."

Trudeau said he fully expected the Tories to come up with vicious attack ads after the Liberals choose their leader, because "that is what they do."

"It's fundamentally about suppressing the vote, about convincing people to stay home and to disengage," he said.

The result, he added, is increased cynicism and low voter turnout.

Harper has also turned many voters off with his rigid efforts to control his MPs, Trudeau said.

"People are tired of electing good people to be their voices in Ottawa, and instead getting representatives of Mr. Harper back in their communities."

Trudeau said he jumped into the race because the Liberals were "looking for quick fixes still" and he felt he had something the country needed.

What's clear, he said, is that the middle class is "struggling" under stagnant incomes and rising costs, arguing that a strong middle class helps boost society's "most vulnerable."

He offered few specifics on what he would do to boost the economy — assuming he gets the opportunity.

"A leadership campaign is not a time where you put forward a platform you try to sell for the next two years," Trudeau said during an earlier stop at Ryerson University.

"It's about actually generating the platform that will allow us to develop the kind of strong policy platform that will answer all of your questions in 2015 in time for the election."

Trudeau is widely seen as the front-runner heading into the Liberal leadership vote next month.