Defence Minister Peter MacKay is denying the Department of National Defence tried to hide details of its military spending by quietly awarding a $105-million contract to a German company to build armoured vehicles.

Speaking exclusively to CTV's Question Period, MacKay said information about the project was readily available online.

"That information was on a DND and Public Works website for three years," MacKay said in an interview that will air Sunday. "It was released accurately in detail at the time … and suggestions otherwise are simply false."

However, critics say that DND's website did not include an announcement that the contract was awarded to the German firm FFG. A notice about the deal was posted in April on an industry website where companies can bid on government work.

"The fact they didn't issue a press release suggests they didn't want people to know about it. So it gives a perception they were nervous about this, and they were trying to cover it up," said Steven Staples, president of the Rideau Institute, an Ottawa-based think tank that has scrutinized DND's spending figures.

MacKay is fighting back after weeks of attacks from opposition parties. On Friday, he was accused of downplaying the true costs of Canada's mission to Libya last year.

The incremental cost of the mission was double the $50-million figure MacKay gave last October, a report by the Rideau Institute showed.

Recently released figures show the incremental cost of the Libya mission was $103.6 million. The full cost of the mission was $347 million. The DND typically only reports the incremental costs of military missions to the public -- expenses considered above and beyond normal operating costs.

MacKay told Question Period that the initial figure he provided was true in the early days of the conflict.

"I believe there's a deliberate attempt to confuse the public and then blame that confusion on me. When I said the cost was $50 million to date, that's exactly what it was to date," he said.

MacKay said he always cautioned the final price could increase since wars are unpredictable.

But critics say the Conservatives have a long history of hiding the true costs of projects, from the proposed F-35 purchase, to the new tank contract.

"It's difficult to understand somebody who represents the government, a minister of crown, can so consistently mistake numbers to the public," NDP Leader Thomas Mulcair said.

With a report from CTV's Richard Madan