A decision by the Canadian government could mean Australia’s 70 F-35A jets cost $100 million more.

Just days after Defence Force officials told Senate Estimates that the total budget for the F-35A project was now $17 billion, Canada appears to be getting cold feet.

The country’s newly-elected prime minister Justin Trudeau says Canada will not buy its planned 65 F-35A jets, and will instead put out a new tender for something to replace the aging CF-18 jet.

At a congressional hearing after Mr Trudeau’s announcement, head of the JSF program US Air Force Lieutenant General Chris Bogdan said it would force up the cost for everyone else.

“If there are 65 less A-model airplanes in that production profile from any country, whether it be Canada or someone else, we have estimated that the increase in price for everyone else is about 0.7 to 1 per cent,” Lieutenant General Bogdan told the House Armed Services Committee.

“For an A-model today that's about $US1 million a copy.”

As Australia plans to buy another 70 of the planes, Canada’s decision could mean the bill is almost $100 million more.

Canada's withdrawal will also see the cost of follow-on development programs increase, as Canada had pledged to cover about 2 per cent of that cost.

A spokesperson for the Australian Strategic Policy Institute told reporters that Canada's departure was a big blow for those still involved.

“It's not great news for the program, there's no two ways about that,” he said.

“One of the fundamental selling points of the Joint Strike Fighter program was multinational by giving economy of scale for everyone and also interoperability between the United States and its various allies.

“You take a hit on both if one of the major partners pulls out.”

Some experts say Canada has made a wise decision, given the long-running and well-publicised problems with the mind-numbingly expensive engineering project.