Conservative Leader Stephen Harper says the cost of Canada's new stealth fighter jets is still within budget, even after the department in charge confirmed the original price will rise.

The Department of National Defence confirmed Monday to The Canadian Press that officials have been told the cost of Lockheed Martin's F-35 fighter jets is expected to jump.

The statement comes after several official reports from the U.S. government said the price has risen from the original 2001 estimate of $75 million per plane, cited frequently by the Conservatives.

The latest one comes from the Pentagon, which recently told the U.S. Congress there are a number of increases in the $382-billion (U.S.) development of the advanced fighter-bomber.

The latest reports put the Conservative leader on the defensive on Tuesday.

At an event in Quebec, Harper said the federal government can still pay for the fighter jets and fall within the budget if a multi-billion dollar contingency fund is used.

"Many of the reports you're citing are comparing apples to oranges. Our experts have put out their detailed figures and everything we've seen is within those figures and their contingencies — the contingencies that have been allowed," Harper said.

A statement issued by the Department of National Defence said it had not received a copy of the Pentagon report.

The statement said once it receives the report, the department "we will be able to assess how it may impact the cost of Canadian production aircraft."

The new Pentagon report suggests Canada could pay up to $24 billion over 30 years to maintain 65 planes.

That's even more than an estimate from Kevin Page, the parliamentary budget officer, who has said it would cost $19.5 billion to maintain the high-tech planes.

'This thing is out of control'

The latest reports on the potential cost increase associated with the controversial fighter jets sparked immediate reaction from the other political leaders campaigning across the country.

Liberal Leader Michael Ignatieff said Harper simply isn't telling the truth when it comes to the costs of the fighter jets.

"And the thing that is so mendacious about what the government is doing is that they say to the Canadian people we can get you the plane at the right price. Let me tell you folks. Not even President Obama knows what the planes are going to cost. This thing is out of control."

Bloc Québécois Leader Gilles Duceppe challenged the Conservative leader to release all the information he has on the fighter jets.

"What we've said since the very beginning and when Mr. Harper is saying, he [doesn't] want to withdraw a contract, that means there's a contract. It's time until next Monday that he showed us that contract," Duceppe said.

Meanwhile, NDP Leader Jack Layton said he has grave doubts about the purchase of the fighter jets. But the NDP leader said he wanted to initiate a national discussion about defence needs if he's elected on May 2.

"We've got issues of our own sovereignty, we've got the north, we've got questions of disasters that might take place and equipment that might be required, whether it's elsewhere in the world or right here in Canada," Layton said.

"Let's have a full discussion of what the equipment needs are and what the priorities should be."