10/02/2014 12:29 EDT | Updated 12/02/2014 05:59 EST

Justin Trudeau: PM 'hasn't even tried' to make case for expanded Iraq role

In his first major speech on the future of Canada's role in Iraq, Liberal Leader Justin Trudeau left the door open for his party to back an expansion of the 30-day non-combat mission that is set to wrap up on Friday.

But he made it clear that he hasn't been won over by Prime Minister Stephen Harper's rhetoric on "the nobility of combat."

- ANALYSIS | Harper readying groundwork for Canada's turn in Iraq

In a mid-morning speech to a mostly left-of-centre crowd attending an annual policy conference organized by Canada 2020, Trudeau pointed out that, as yet, Canadians "don't know exactly what he has offered the Americans."

"We don’t know what our role will look like. We don’t know how long our contribution is expected to last. We don’t know how helpful our CF-18s will truly be," he added.

All those unanswered questions, he said, "makes Canadians understandably anxious."

"Mr. Harper is intent on taking Canada to war in Iraq,"Trudeau stressed. "He hasn't made the case for it. He hasn’t even tried."

Canada can have 'significant' non-combat role: Trudeau

The prime minister, Trudeau said, "would have you believe that Canada’s best contribution to this effort is a handful of aging war planes," but he believes that there could be "significant, substantial, non-combat roles" for Canada in everything from humanitarian aid to political reform.

"This is something we do well."

During a post-speech chat on stage with Canada 2020 president Don Newman, Trudeau noted that there are "hundreds of thousands" of displaced people in the region who don't want to leave because "that's where their homes are."

"They need support to get through this very, very difficult time, and Canada has a capacity and expertise in doing just that," he pointed out.  

"Why aren't we talking more about the kind of humanitarian aid that Canada can and must be engaged in. rather than, you know, trying to whip out our CF-18s and show them how big they are? It just doesn't work like that in Canada." 

- WATCH: Trudeau to Harper: Do more than 'whip out CF-18s and show them how big they are'

- WATCH: Trudeau's remarks to the Canada2020 conference

- READ: Kady O'Malley's liveblog from the Canada2020 conference

Under questioning from reporters following the speech, Trudeau stuck to his contention that the onus is on Harper to sell parliamentarians — and Canadians — on any proposal to expand Canada's role beyond the advisers already on the ground.

Asked what the optics would be of Canadian troops heading overseas without at least one opposition party voting to support the mission in the House, Trudeau indicated that he saw that as the prime minister's concern.

"This should be beyond partisanship."

MPs could be asked to vote on an expansion of the current mission as early as next Monday.

The government is expected to provide more details on the next phase of Canada's participation, which will likely include taking part in the airstrikes already underway.

Mobile users can read Kady's live blog here