Liberal MP Belinda Stronach rose in the House of Commons on Friday to ask her former flame Foreign Affairs Minister Peter MacKay for an apology after he allegedly referred to her as a dog -- a remark he has denied making.

"Yesterday during question period the minister of foreign affairs used a very inappropriate word to describe me. This is not the first time he and his party have revealed their true colours regarding respect for women and politics and how chilling this behaviour is for women who contemplate entering politics," Stronach said, raising a point of order.

"For that Mr. Speaker I simply ask that the minister of foreign affairs apologize to this house."

According to the rules of parliamentary debate, MPs have the right to raise a point of order after it's deemed that a violation of the rules of order in the House Commons may have taken place.

Possible violations include: using "unparliamentary language," accusing someone of lying, and failing to refer to others in the third person.

House Speaker Peter Milliken responded by saying that he did not hear the comments or see any of the gestures that are alleged to have taken place.

But he cautioned MPs to use proper language and show respect for each other in the Commons.

MacKay's comment came during a heated exchange in the House of Commons over the government's new Clean Air Act.

While the government was being peppered with questions about the new Clean Air Plan, Liberal MP Mark Holland says a Liberal jokingly asked MacKay about the impact of pollution on humans and animals: "What about your dog?''

According to Holland, MacKay motioned toward Stronach's empty seat and replied: "You already have her.''

"Mr. Speaker, this is clearly shameful and the minister owes an apology to this House," Holland said Thursday. "It is a shameful display that he absolutely must apologize for."

Liberal MP David McGuinty said the remark was loud and unmistakable.

"At least 10 members of our caucus heard it loud and clear and it would be very very difficult for the minister of foreign affairs to deny what he said,'' McGuinty said Thursday.

MacKay repeated his assertion Friday that he did not say anything derogatory about Stronach and suggested his critics check the record of Hansard.

"I made no comment," he told reporters after touring a sewage treatment plant on the Halifax waterfront. "It's not there. It's not there. I said nothing about a dog,'' he said.

When pressed further by reporters, he answered: "I'm not going to answer questions about something as silly and scurrilous as what the Liberals have tried to bring up time and time again for the last year.

Dan Dugas, a spokesperson for MacKay, argued Thursday that the insult may have never have been uttered because it wasn't transcribed.

"I've checked the official record of House proceedings and there is no such comment," he told The Canadian Press.

But such transcripts usually omit or skip any comments during heckling.

When told that MacKay denied making the comment, Stronach told reporters that she trusted the judgment of her colleagues who said they heard the remark.

"I am even more disappointed today as I reflect on the character of this government, we saw it during question period, no one is willing to take responsibility for this and I am worried for the women of Canada how this kind of attitude translates into policy development and the actions that this government is taking.

It wouldn't be the first time that the foreign minister compared his ex-girlfriend to a canine.

MacKay and Stronach, who were romantically linked while serving as caucus colleagues last year, suffered a highly public split when Stronach left the Conservative party to join the Liberals.

Shortly after her defection in May 2005, MacKay retreated to Nova Scotia to "clear his head" as he then explained.

The Globe and Mail showed a picture of MacKay looking thoughtful as he posed on his property with a dog.

But it was later revealed that the dog did not belong to MacKay.

A recent book by National Post columnist Don Martin described MacKay's "volcanic fury" when Stronach revealed her plans to leave the Tories.

"Belinda: the Political and Private Life of Belinda Stronach" also suggests his fiery reaction was enough to make Stronach reconsider her decision.

"Maybe I was naïve in some ways," Stronach told Martin. "I still think it's possible to see someone in an opposite party. Clearly he didn't agree. I would've liked another day to talk him through it."

With files from The Canadian Press