National Defence Minister Harjit Sajjan has tapped four eminent Canadians to help him craft a comprehensive plan for the military's size and scope in the future.

The blue-ribbon panel that will review Canada's defence policy includes a former Supreme Court justice, a former top soldier, a retired cabinet minister and former top bureaucrat.

The ministerial advisory panel members are:

Louise Arbour, a former Supreme Court justice, member of the advisory board of the Coalition for the International Criminal Court and former UN high commissioner for human rights.

Bill Graham, former Liberal minister of foreign affairs and national defence.

Ray Henault, former chief of the defence staff and past chair of the NATO military committee.

Margaret Purdy, former associate deputy minister of national defence.

Sajjan said an online portal will also allow Canadians to engage in the defence policy review, as well as a series of public roundtables. The Senate and House of Commons defence committees will also play a "critical role" in the process, he said.

Last review in 1994

Sajjan said the last time a review of this scope was carried out was in 1994.

"I think you'll agree, it's long overdue," he said, adding that the results of consultations will be published early in 2017.

The panel will help determine what capabilities will be required in the future, and what equipment will be required to carry them out.

The defence minister could not say how much the advisers would be paid, or how much the review process would cost. But he said the process will be "credible and relevant."

Prime Minister Justin Trudeau explains to reporters in Trois Rivieres why the review is necessary 2:06

Prime Minister Justin Trudeau was also asked how much the review process would cost, but he deferred to the minister and said he did not have a figure. The consultation process will guide procurement, training and force size as the military adapts for the future, he said.

Keeping Canadians safe

"The fact is, Canada has for many years not put forward a comprehensive vision of what our military should be doing, how best we can have an impact on the world, how best we can keep Canadians safe, what kinds of things we're expecting our military to be engaged in the coming years, in the coming decades," Trudeau said.

Former Supreme Court justice Louise Arbour is one of four members of an advisory panel for Canada's defence policy.

Arbour said use of force is only one component, and that the defence policy must be linked to foreign policy and diplomatic engagement at a time when non-state actors change the course of traditional warfare.

A key question is what role Canada should play, Arbour said in an interview with CBC News Network.

"Should we just be a 10 per cent addition to our allies' operations, whether it's NATO or in various combinations of what they call 'coalitions of the willing?'" she said. "Or should we be looking at carving a special niche, and if so, what is it that Canada can contribute?"