Prime Minister Stephen Harper says he has no reason to believe anyone planted electronic bugs in the home of disgraced former foreign minister Maxime Bernier's ex-girlfriend.

"I have absolutely no information to suggest that's true," he told reporters in Paris on Tuesday, reacting to a question about the allegation by Julie Couillard.

In an interview with Quebec's TVA network broadcast on Monday, Couillard said experts had checked her home and told her that listening devices had been installed and removed.

"Apparently, there were some (listening devices) in the boxspring of the mattress in my bedroom," she said in the interview.

Harper said, "The government of Canada does not intend to get into the business of investigating private citizens."

The prime minister also said there have been no expressions of alarm from NATO partners over the security breach that led to Bernier's resignation.

"Right now, we have no information that secrets were (revealed)," he said.

He insisted Bernier's resignation had nothing to do with the former minister's relationship with Couillard, who had links to the biker underworld as recently as 2005.

The documents -- relating to the early April NATO summit in Bucharest, Romania -- contained classified and secret information, sources tell CTV.

Thomas Mulcair, the NDP's deputy leader, told CTV Newsnet that Harper will have to explain the contents of the documents when he returns from Europe. Harper declined to answer questions about the documents' contents.

"Classified documents are classified, and I do not discuss classified documents," Harper said in Paris.

Robert Fife, CTV's Ottawa bureau chief, told Canada AM earlier on Tuesday that it's likely the RCMP will be asked to investigate the extent of the breach.

"We don't know what other secrets and cabinet documents he shared with this woman (Julie Couillard)," he said.

Some politicians called for such an investigation.

On Monday, NDP Leader Jack Layton told reporters: "Only a police force can sort through the kind of allegations and statements that are emerging here.

"All of these add up to the need for someone who's going to be arm's length, dispassionate and concerned about the public interest to get to the bottom of it," he said.

Harper announced Bernier's resignation hours before Quebec's TVA network broadcast an interview with Couillard, during which she recounted finding the papers.

• Bernier's ex-girlfriend says she was 'humiliated as a woman'

Fife said Couillard didn't have the security clearance necessary to have those documents in her possession.

"(Bernier) is not to share any top-secret information with anyone unless they have the same security clearance as he does, and clearly Ms. Couillard does not," Fife said.

This scandal could blacken Canada's reputation with its allies, a security analyst told Canada AM.

They will be saying, "'What's going on over there? Can we share information with these guys?'" former CSIS agent Michel Juneau-Katsuya told Canada AM on Tuesday.

However, Joe Clark a former prime minister and external affairs minister in the Brian Mulroney era, told Canada AM that the test is in the response.

"What the world will note is that when a problem arose, it was addressed," he said.

The prime minister appointed International Trade Minister David Emerson as the interim foreign affairs minister. Clark praised Emerson's abilities, saying he has a "clear understanding of domestic and international affairs" and should be considered for the post on a permanent basis.

Bernier: A troubled minister

Bernier is a 45-year-old rookie MP who became foreign affairs minister in an August 2007 cabinet shuffle.

Michael Byers, a professor of international law at the University of British Columbia, told Canada AM that the foreign affairs minister is the country's most senior diplomat and should be someone of "great gravitas who speaks to the most serious issues in a reasonable and responsible way.

"Maxime Bernier hasn't lived up to those credentials," he said.

Here are some of Bernier's other gaffes:

• He promised the use of a C-17 military cargo plane to take helicopters to Thailand for cyclone relief work in Burma, but one wasn't available. Ottawa had to spend almost $1 million to rent a Russian aircraft.
• At the tail end of a visit to Afghanistan, Bernier let it slip to reporters that he thought Asadullah Khalid, governor of Kandahar province, should be replaced.
• He confused the name of Haiti's current president with the previous one on a trip to the Caribbean country.
• Harper left Bernier behind on some recent foreign trips, although he took along other ministers.
• Bernier often sat in his seat during recent question periods as other ministers were called upon to speak on foreign affairs issues.

The Liberals had been calling for his dismissal in recent days.

"Why should the government have to keep cleaning up after this minister? Wouldn't it just be easier to get rid of him?" asked Deputy Liberal Leader Michael Ignatieff in question period on Monday.

Conservative House Leader Peter Van Loan said Bernier "had been showing considerable leadership on the world stage." But when Harper had been asked earlier Monday at a news conference whether he still had confidence in Bernier, he wouldn't answer the question.

Many observers predicted Bernier would be moved to another portfolio if Harper shuffled his cabinet again this summer.

Harper told a news conference Monday that Bernier's fate is a warning to other members of cabinet.