Canada's government on Wednesday widened its multi-billion-dollar search for a new fighter jet to models other than the F-35 it has spent 15 years helping the United States and other allies to develop.

Ottawa is "hitting the reset button" on the procurement, Public Works Minister Rona Ambrose told a press conference.

Earlier this year, Ambrose was tasked with overseeing the largest government procurement in Canadian history after it came under fire over its spiralling costs and an apparent lack of transparency and competition in the process.

Officials did not say which other aircraft may be considered as a replacement for its aging fleet of CF-18 fighter jets, due to be retired in 2020, nor when a final decision may be expected.

But Boeing complained earlier in the process that its Super Hornet fighter had not been considered while Ottawa was still focused on the F-35.

"No decision has been taken on a replacement for the CF-18s," a senior government official told a media briefing.

An independent report for the government said all "fighter aircraft that are currently in production or scheduled to be in production" are in the running.

Opening up the process to bidding does not preclude Canada sticking with the F-35, which the government and the military still appear to favor.

Canada, the United States, Britain, the Netherlands, Denmark, Australia, Turkey, Italy and Norway are jointly developing the F-35 fighter.

Seventy-two Canadian companies are involved in the program, with contracts estimated to be worth $438 million (335 million euros).

In 2010, the government calculated the cost of acquiring 65 F-35 Joint Strike Fighter jets at Can$9 billion, plus maintenance over 20 years for a total of Can$25.1 billion.

At the urging of the auditor general, on Wednesday the government released a new estimate of the costs over a longer 42-year period between 2010 to 2052.

According to revised estimates by consulting firm KPMG for the government, the 65 jets would cost Can$45.8 billion over 42 years.

These costs include development, acquisition, maintenance and operation of the aircraft based on 11,700 annual flight hours -- 20 percent fewer than the CF-18s currently fly -- as well as initial pilot training.

But Defense Minister Peter MacKay said all the estimates are "based on cost assumptions" and "will continue to be refined in the years to come no matter what aircraft Canada purchases."

He insisted the government would not spend more than Can$9 billion to purchase new jets.

MacKay also suggested, citing a Canadian general's recent testimony before lawmakers, that if necessary the life of the existing CF-18 fleet could be extended by up to 15 years to 2027 if this new process delays the purchase.