A Tory MP known for his partisan attacks and bare-knuckle parliamentary style is facing accusations of racism after he twice used the term "tar baby" in the House of Commons Friday.

Conservative MP Pierre Poilievre, parliamentary secretary to the prime minister, used the term in response to Liberal Leader Michael Ignatieff's decision to back away from his predecessor's unpopular carbon tax policy.

"On that side of the House, they have the man who fathered the carbon tax, put it up for adoption to his predecessor and now wants a paternity test to prove the tar baby was never his in the first place," said Poilievre.

He used the term again later during question period.

Liberal MP Ralph Goodale raised the issue at the end of question period and asked that Poilievre apologize for using the term.

"In addition to being a pejorative term, which might well prove to be unparliamentary, the parliamentary secretary might consider that there are many authorities both in this country and many others that consider the term racist," said Goodale.

Responding, Poilievre said he wasn't aware that the term had racist connotations.

"I have worked hard to represent people of all backgrounds and I have always done so in a spirit of tolerance. My reference to the term 'tar baby' was a common reference that refers to issues that stick to one," he said.

Poilievre hasn't officially apologized and the controversy continues to spread in Ottawa.

Later on Friday, Liberal MP Marlene Jennings, who is black, decried the term and demanded an apology.

"As a black child growing up, I was called all sorts of pejorative names based on the color of my skin, including the 'n-word' and 'tar baby' -- and believe me, it was hurtful," said Jennings.

"I am offended by Mr. Poilievre's insensitive remarks --and I know leaders in the black community across Canada feel the same way."

However, the prime minister's office appears to be digging in its heels and refusing to apologize.

In a press release issued Friday afternoon, the PMO stated that the term has been used by national media in Canada for something that sticks.

Tory MP Andrew Saxton said his "colleague meant no harm" when he used the term.

"It's a completely different usage of the term -- it's a usage that's been used for a very long time (and used) by many politicians, including Liberals," he told CTV's Power Play on Friday.

Still, ignorance is no excuse, said NDP MP Malcolm Allen.

"It's not an excuse to say 'I'm a younger person and I don't remember those terms,'" he said. "He ought to (have) apologized this morning."