OTTAWA - The powers of Parliament are being put to the test in the political battle over access to uncensored documents in the Afghan detainee affair.

Justice Minister Rob Nicholson weighed in Wednesday, arguing that Parliament has no authority to demand unfettered access to documents related to the alleged torture of prisoners handed over to Afghan authorities by Canadians soldiers.

He rejected the opposition parties's contention that the government has breached parliamentary privileges by ignoring a Dec. 10 order, passed by the House of Comons, to produce the uncensored documents.

"I would remind the House that our parliamentary privileges are not indefinite nor unlimited," Nicholson told the Commons.

"The exact scope of those privileges has been a matter of debate since Confederation."

Nicholson said the government has a duty to protect information that could jeopardize national security, national defence, international relations and even potentially the lives of Canadian troops in Afghanistan.

And he said Parliament is not immune to the laws of confidentiality on such matters, citing a Supreme Court of Canada ruling that concluded "legislative bodies . . . do not constitute enclaves shielded from the ordinary law of the land."

He also cited numerous examples in Canada, Britain and Australia in which the government's duty to protect sensitive information outweighed Parliament's right to know.

"This debate is not new, nor is it limited to Canada. And while one might argue that in theory the House has absolute powers, Canadian and other commonwealth examples demonstrate that this has not been recognized in practice."

Nicholson was rebutting arguments made two weeks ago when the three opposition parties asked Commons Speaker Peter Milliken to rule that the government has breached their parliamentary privileges by refusing to comply with the order to produce documents.

Milliken told the Commons he won't rule immediately on the matter.

Should he rule in favour of the opposition parties, they've served notice they'll follow up with motions censuring the government and three top ministers -- Nicholson, Defence Minister Peter MacKay and Foreign Affairs Minister Lawrence Cannon.

That could theoretically result in incarceration of the ministers until the end of the parliamentary session.

However, if it came to that, the government could take the issue to court or force an election on the matter.

If the Conservative government has its way, Milliken may never have to rule on the issue.

Even before Nicholson made his case, Tom Lukiwski, parliamentary secretary to the government House leader, told Milliken that the Dec. 10 order to produce documents is procedurally "invalid." He said a demand for documents of this sort can only be made via a "warrant of the Crown" -- that is, by asking the Governor General.

So far, the government has released thousands of pages of documents, most so heavily censored that little can be deduced from them.

Should Milliken conclude the government must turn over uncensored documents, the NDP and Bloc Quebecois are jointly proposing a motion that would require the special all-party committee on Afghanistan to come up with mechanisms to protect sensitive information.

Nicholson noted, however, that the original order to produce documents made no provision for satisfying national security concerns. In the absence of such protection, he said the government acted reasonably by appointing former Supreme Court justice Frank Iacobucci to review all documents and determine which can be safely disclosed.

"The government took this step to offer a very reasonable compromise between the complex and serious interests at stake," he said, maintaining that the government has "consistently tried to facilitate the work" of the Afghan committee.

Opposition parties contend the Iacobucci review is simply a stalling tactic. They note that no time limit has been put on his review documents.