The federal government has not dismissed the prospect of backing out of the F-35 stealth fighter jet program, associate defence minister Julian Fantino told a House of Commons committee Tuesday.

"We have not, as yet, discounted the possibility, of course, of backing out of any of the program," Fantino said.

He made the comment under questioning from members of opposition parties.

Fantino said the government remains committed to buying the jets, although no contract has yet been signed. However, he also told the all-party committee the government is still considering "if and when" to sign the contract.

It's a significant change in tone as the Conservatives have been adamant that the purchase of the jets is a priority for Canada's military.

In 2010, the Conservative government announced they intended to buy 65 F-35 jets to replace Canada's aging CF-18 fighters. At the time, the government said the first jet could be ready by 2016 and the purchase of the jets would cost $9 billion.

However, Lockheed Martin Corp's F-35 program has hit several setbacks. The U.S. and several other nations have scaled back their orders.

The U.S. delayed the purchase of 179 F-35 jets to at least 2017 in order to save $15.1 billion. Italy has also cut its order from 131 to 90 planes and Turkey has halved its order.

Fantino insisted his government would not leave the air force in the lurch when the CF-18 jets reach their intended retirement date in 2020.

The Conservatives have been under increasing political pressure on the F-35 program as the opposition paints the jets as a luxury purchase at the expense of other areas of government spending, such as pensions.

However, outside of the committee, Fantino denied the Conservatives are backing down from their commitment.

"I'm being realistic," he said. "Until such time as the purchase is signed and ready to go, I think the only appropriate answer for me is to be forthright. We are committed to the program. We intend to do the best we can for our men and women and Canadian taxpayers with respect to replacing the CF-18."

Two weeks ago, Canada took part in a consortium meeting with the manufacturer, where a higher potential unit price was discussed.

That meeting forced the government to finally wake up to the real cost of the jets, said Liberal defence critic John McKay.

"I think he had a reality check, however you want to spell ‘cheque,'" he said.

NDP MP David Christopherson agreed, and said that the government is now backing away from the deal because it simply isn't worth the cost.

"They're in serious trouble here. This plane is not working. This plane is not flying," he said.

Analyst Steven Staples, from the Rideau Institute, said that Fantino's comments may have been designed to provide the government with some space on the issue in the coming months.

"They're trying to create some wiggle room for themselves, if the project continues to go as badly as it's going now," he said.

With a report from CTV's Roger Smith