Canada's new defence minister is warning against haste in coming to a decision to replace six CF-18 warplanes with new military trainers.

In an interview with CBC News, Defence Minister Harjit Sajjan said Canada must be cautious in assigning troops to a new training mission and carefully select its partners, both on the ground in Iraq and in the allied coalition.

"When we make this decision, it's going to have a meaningful impact and not create other problem for us," he said, warning against a negative "ripple effect."

Sajjan said the role is important — crucial even — and must not be dismissed as an inconsequential military effort.

"It's going to be a meaningful contribution to the fight against ISIS," said Sajjan. "And in our opinion, the training mission is the one to do it."

Sajjan said training was a perhaps overlooked effort, one that has the potential to be a game-changer in Iraq.

The ability of ISIS fighters to take ground came as a result of Iraqi military failures, Sajjan said. The force simply crumbled in the face of the extremist forces.

"So if we do not focus on the training mission, imagine where are we going to be? The end result has to be with them, not only regaining the ground, but also then holding it as well," Sajjan said.

Re-tooling Canada's mission

Canada currently has 69 special forces trainers based in the northern part of Iraq on what is known as an advise-and-assist mission with Kurdish Peshmerga fighters.

The Kurdish region is semi-autonomous inside Iraq, but the central government, such as it is, has not let go of its claim to that territory. Any expanded Canadian effort in the Kurdish region risks inflaming tensions in Baghdad and in Ankara, the capital of neighbouring Turkey, which has for decades had its own trouble with Kurdish national ambitions.

Harjit Sajjan talks to the CBC's James Cudmore about the expansion of Canada's training mission in northern Iraq 1:15

There are other potential partners in Iraq, but they're also problematic.

The national army is a largely Shia force whose own alleged excesses against Sunni Iraqi civilians are said to have contributed to early support in Iraq for the forces of the Islamic State.

There are Shia forces, but some are deeply allied with the Iranian regime and are trained and supported by the Iranian Revolutionary Guard. Sunni militias are also active in Iraq, but it too is a force with its own agenda, one that might align today with Canada's but perhaps not tomorrow.

Sajjan says the government is aware of this challenge and looking at ways to best ensure its forces contribute to the defeat of ISIS and without fomenting sectarian tensions.

"We're very mindful of the political dynamics that are at play," the defence minister said. "But we want to make it very clear: Our contribution that we're doing is to take the fight to ISIS … making sure that when we make this decision, it's going to have that meaningful impact and not create other problems for us," Sajjan said.

Canada's impact

The former soldier and police officer said his own experiences, including fighting gangs in Vancouver and the Taliban in Afghanistan, have led him to understand the importance of tribalism and sectarianism and its role in insurgency and violence.

"We have to understand that it's not just one issue, everything is interconnected and we have to understand those linkages," Sajjan said. "If we don't, we're not going to be able to assess when we do something, is it going to create the positive impact that we want?

"Because the last thing we want to do is do something that's going to think we're going to create a positive impact, but it actually creates a negative one."

The minister offered no new information about the size or composition of the new training force. All the options are still on the table, Sajjan said.

But the prime minister has hinted broadly the training effort would resemble the 800-strong force deployed to Afghanistan following the end of combat for Canada there in July 2011.

Canada's contribution there was part of a much larger NATO-led training mission in Afghanistan comprising soldiers from more than 40 nations.

Sajjan says he expects a similar coalition-style training mission will eventually be cobbled together to support anti-ISIS efforts in Iraq.

"I trust in the entire military leadership with all the countries involved, that they've already been seized on this and looking at the wider picture," Sajjan said.