Canada plans to order 18 Boeing F/A-18 Super Hornet fighter jets while seeking offers to update the rest of its aging combat fleet, Defense Minister Harjit Sajjan announced Tuesday.

Sajjan said Canada will remain a partner in the development program of Lockheed Martin's F-35 stealth fighter jet, even as it looks for a replacement for its aging CF-18s.

Canada had ordered 65 F-35 stealth fighters in 2010, but Prime Minister Justin Trudeau scrapped the deal because of sky-rocketing costs.

The 18 Super Hornet fighter jets will be deployed from 2018 as the government awaits offers on a longer-term fleet replacement, Sajjan said.

Canada's current fleet of fighter jets is more than three decades old and is down from 138 aircraft to 77.

The Super Hornets will help fill a "capability gap" and allow Canada to meet its NATO and NORAD security obligations, said Sajjan.

"The number of mission-ready planes we can put in the air today is less than the NORAD and NATO obligations taken together," he said.

As well, he said, measures will be taken to extend the working life of the existing CF-18 fleet through to the late 2020s, when the new fleet should be "fully operational."

Canada's CF-18 fighter jets were built by McDonnell Douglas, which merged with Boeing in 1997. They were originally scheduled to be retired in 2020.

Canada joined the United States and its allies in 1997 to develop the F-35 Lightning II stealth fighter.

But after coming under fire over its spiralling costs and an apparent lack of transparency in the procurement process, the previous Tory government widened the search for a new fighter jet in 2012.

The new five-year procurement process will begin early next year.

That will mark the second reboot in four years of the largest military procurement project in Canadian history.