BRAMPTON, Ont. -- A new Liberal government would take a long look at any trade deal signed by the Tories before deciding whether to uphold it, party leader Justin Trudeau said Sunday.

"We will of course evaluate and look at what's in the deal," he said in Brampton after a boisterous and crowded rally with dozens of Ontario candidates.

"The problem is that (Prime Minister Stephen Harper) has been secretive and non-transparent in this and we need to make sure that we're actually creating a trade deal that is good for Canadians."

Twelve countries including Canada appeared Sunday on the verge of creating the world's largest regional trade zone, which would usher in a series of economic changes on four continents and prompt months of heated debate -- starting with Canada's election.

"These are some of the largest economies in the world coming together to sign this deal," Trudeau said. "It's important that Canada be part of it."

The Liberal party favours trade, he said.

"It's good for creating jobs, good for growth and the economy and that's what we're going to look at."

Trudeau made the remarks after a massive, high-energy rally at a local arena that featured 75 candidates and several thousand cheering supporters from the seat-rich suburbs around Toronto.

Up to 100 school buses yellowed the parking lot, but inside it was all Liberal red as Trudeau delivered a fiery speech positioning himself as a builder of bridges to counter Harper's habit of dividing the country.

With Liberal grandees such as former prime minister Paul Martin in attendance, Trudeau said it was time to end the Conservative government's practice of pitting Canadians against each other.

"The prime minister's job is to bring Canadians together, not to tear us apart," he told a crowd filled to the rafters of the Powerade Centre.

"For 10 years, Stephen Harper has never missed an opportunity to divide Canadians. East against west, urban against rural, French against English, so-called old stock Canadians versus newcomers. His first instinct is to appeal to the worst instincts."

The ethnically diverse crowd cheered loudly, applauded and chanted, "Trudeau, Trudeau," as the Liberal leader painted himself as someone who seeks to unite Canadians.

"Conservatives are not our enemies. They're our neighbours.

"We don't need to convince them to leave the Conservative party. We just need to show them how Stephen Harper's party has left them."

Trudeau's message to Brampton is a carefully calculated one. The city is one of the most diverse in the country and has seen its population more than double in the last 20 years, growing to more than 520,000 people.

It may also be key to unlocking the doors to power. It is located in the 905-belt that surrounds Toronto, a highly coveted, vote-rich region.