OTTAWA - Prime Minister Stephen Harper continues to insist there are no security concerns about Maxime Bernier's recent relationship with a woman with past ties to criminal bikers - despite firing his foreign minister over a related security lapse.

But all three opposition parties are demanding an inquiry into the matter, which saw Bernier leave classified documents in April at the home of Julie Couillard, his then-girlfriend.

They want to know why no one noticed the documents were missing for five weeks, whether Bernier was as careless with other secret papers, and whether Couillard had access to any of them.

Harper suggested Tuesday that Bernier's resignation late Monday put an end to the matter. Harper said Bernier broke rules by leaving the documents unsecured, but he added that the papers have now been returned to the government and there are no security concerns.

Harper also said he has no reason to believe that anyone planted listening devices in Couillard's apartment, as she has claimed.

"I have absolutely no information that would suggest that is true," Harper said in Paris, where he started a three-day European trip.

In Ottawa, government House Leader Peter Van Loan confirmed that the documents were related to a NATO summit held in April in Bucharest, at which Canada sought reinforcements for Canadian troops in Afghanistan.

Van Loan insisted Harper learned only Monday that Bernier had left the documents unsecured and took action immediately.

But Liberal Leader Stephane Dion suggested the government would have discovered the missing documents weeks ago had it heeded opposition calls to explore the national security implications of Bernier's relationship with Couillard.

Instead, Dion said Harper showed "an appalling lack of judgment" by dismissing opposition concerns and accusing them of prying into Bernier's private life.

Ralph Goodale, the Liberal House leader, said the government only fessed up Monday to the security breach because Couillard was about to tell all in a television interview that night.

"The government's credibility is in tatters . . . Why do they only take things seriously after they get caught?" Goodale asked in the Commons.

Van Loan reiterated that the Foreign Affairs department is conducting an internal review of the matter, but didn't offer any details.

Opposition parties insisted an independent inquiry is necessary, although they disagree whether it should be conducted by the RCMP or the Commons public safety committee.

For his part, Harper said Couillard is of no interest to him.

"As we've said, private lives are private lives and the government of Canada does not intend to get into the business of investigating private citizens.

"This has nothing to do with Madame Couillard. This was the unfortunate error, the unfortunate actions of the minister that are at issue here.

"You obviously don't disclose classified materials and you certainly take adequate care to ensure that they are not disclosed and they are not left behind somewhere."

Several current and former cabinet ministers found it hard to imagine how classified documents could go missing for so long.

Goodale said all cabinet documents are numbered and logged out to ministers by the Privy Council Office, the administrative arm of the prime minister's office. If a document isn't returned in timely fashion, he said, PCO calls to check where it is.

Revenue Minister Gordon O'Connor said he doesn't take any classified documents outside his office.

Defence Minister Peter MacKay said he has a safe in his home and his office in which to secure secret papers.

Couillard said that when she found Bernier's material, she contacted a lawyer, and it was returned to government officials. She said she never read the documents.

She also said in a broadcast interview that private-sector experts swept her home for listening devices in the last three weeks as a controversy raged over her recent relationship with Bernier. She said they found evidence that bugs were removed recently, including in the box spring of her bed.

Bernier was the centre of controversy this spring over his relationship with Couillard because of her previous relationships with men connected to Quebec biker gangs as recently as 2005.

Latest From ...