The F-35 Lightning II fighter jet is made by Lockheed-Martin. (Defence Department/Canadian Press)

The Liberals say that if they form the next government, they will put on hold a much-rumoured $16-billion sole-sourced fighter jet contract that is widely expected to be announced Friday by the Conservative government.

In the meantime, the Liberals say they plan to call for yet another reconvening of a House of Commons committee, this time the defence committee, and demand Defence Minister Peter Mackay explain why such a large contract is not subject to a competitive process.

The deal, according to media reports, would see Canada buy 65 F-35 Lightning II fighter jets for $9 billion from Lockheed-Martin. Once maintenance costs over the life of the planes is factored in, the entire program is estimated to cost $16-billion.

Liberal industry critic Marc Garneau said at a news conference Thursday that if this is truly the best deal, then it would win the bid in an open process.

"We just spent $2.6 billion to upgrade our current fleet of CF-18 aircraft and the replacement date that's forecast for these aircraft is not until 2017," said Garneau. "We need to make sure that Canadians get the best possible deal in the circumstances," he said.

Under a previous Liberal government, Canada signed a memorandum of understanding in the 1990s with Lockheed-Martin as part of the company's Joint Strike Fighter program. But Garneau said that MOU does not bind Canada to buying the F-35s.

"The best way to do it, unless it's crystal clear that there is only one candidate that meets the need ... is to go to open tender, open competition, to make sure that the taxpayer is going to get the best deal," said Garneau. "It's not too late to do that."

He argues that putting a stop to such a contract would not be the same as when the Liberals cancelled the contract to build replacement helicopters in the 1990s, a decision that turned out to be more costly in the long run.

Garneau also played down the need to buy the same jets as the U.S. "I would not overplay the importance of compatibility," he said.

But he would not speculate on whether matching what the U.S. is buying is the reason the government might go with the sole-source contract.

"We've got to look at that, get the government to appear before the defence standing committee, to open itself up because it's been extremely secretive."

A $16-billion contract to build fighter jets would be one of the largest military projects in Canadian history, something Garneau says is noteworthy considering rumoured cuts to the Department of Veterans Affairs.