OTTAWA - Any security concerns about Maxime Bernier's former girlfriend wouldn't have come up during his background check because the foreign affairs minister apparently began seeing Julie Couillard after being scrutinized.

Opposition MPs continued to bombard the Conservatives in the House of Commons over revelations Bernier's past companion allegedly consorted with at least two outlaw biker figures in the 1990s.

Some security experts have rejected the government's characterization of the Bernier affair as a private matter, saying questionable personal links could leave the minister -- and Canadian interests -- vulnerable to blackmail or worse.

Bernier, however, had already been vetted by the Privy Council Office and ushered into cabinet as federal industry minister in January 2006 -- evidently before he began dating Couillard.

"I know that the background check is conducted only on candidates to a cabinet position, so not when they are already in a position of a minister,'' said Myriam Massabki, a Privy Council spokeswoman.

"Another background check will not be applied in his case because he's a minister.''

In any event, the system in place since the late 1980s involves scrutiny of just the prospective minister, said Massabki.

"Questions pertain only (to) the candidate, not his spouse, friend, immediate relatives. It's only on the candidate.''

As a result, prickly questions are emerging about whether cabinet ministers get less rigorous security checks than some of their underlings in the public service.

Federal ministers, like senior public servants, are privy to highly sensitive information related to defence, international affairs and national security.

However, it appears a potential deputy minister would be subject to more extensive examination than his or her political boss.

Bloc Quebecois Leader Gilles Duceppe said the apparent discrepancy is a matter of public interest. "I think there should be a security check on the ministers' spouses just like there is on high civil servants.''

Levels of clearance 

Under the government security policy, there are three levels of security clearance: confidential, secret and top secret.

According to the Canadian Security Intelligence Service, top secret clearances require a full field investigation, which involves checking CSIS records, interviewing friends, neighbours and employers, consulting with local police and possibly interviewing the applicant.

Massabki declined to say much about how the Privy Council goes about the background checks for cabinet members.

"It's not only security and criminal concerns, it could be others that could affect the assignment of the candidate for a cabinet position,'' she said.

"We don't want to go into the details of how it's conducted. But it's a Privy Council Office investigation, let's say.''

According to a government official with intimate knowledge of the ministerial vetting process, each candidate for cabinet is interviewed by the prime minister's top aides.

Prospective ministers are asked a series of specific questions, such as whether they owe money, have any history of drug or alcohol problems or any history of criminal problems.

They are also asked general questions, such as whether there is anything in their past that could be used against them, could put them in a conflict of interest or could embarrass the government. And finally, they are asked if there's anything else the prime minister should know about them.

In addition, each candidate is checked out by the RCMP, CSIS and the Canada Revenue Agency.

The official said it's technically correct to say that the process focuses on the individual ministerial candidate, not on his or her family. However, he said the individual's relationships -- and whether or not they might create a conflict of interest or bring the government into disrepute -- are relevant.

While checks are only done once, the official said ministers are always told to advise the prime minister's office or PCO if there are any material changes in their lives, including marital difficulties.

In the case of Bernier, the official said the minister would have been obligated to advise the Prime Minister's Office about Couillard's troubled past, if he indeed knew about it.

One former Liberal minister says when first considered for cabinet he underwent an interview at an Ottawa hotel where he was presented with a file on himself that raised questions about his wife's past political protest activities.

When Jean Chretien's Liberals took office in 1993, party stalwart Mitchell Sharp, the prime minister's ethics adviser, vetted cabinet candidates, a review believed to have disqualified two nominees.