Kitchener, Ont. MP Stephen Woodworth will ask for a special parliamentary committee to discuss the definition of a human being when he rises in the House.
The Conservative MP takes issue with Section 223 of Canada's Criminal Code, which states that human life begins when a child emerges from its mother's body.
"The question is whether that's an accurate statement, an honest statement or a misrepresentation," Woodworth said in an interview.
Canada's been without an abortion law since 1988 when then-prime minister Brian Mulroney's attempt to codify the procedure was struck down by the Supreme Court of Canada. Prime Minister Stephen Harper has repeatedly said his Conservative government will not re-open the abortion debate.
Some pro-life Conservative MPs have attempted to re-ignite the issue. Saskatchewan MP Brad Trost publicly criticized his own government last year for backing an overseas aid group that provided abortions.
Opposition MPs say Thursday's debate wouldn't be happening if Harper wasn't considering re-opening the abortion issue.
"I've never seen anyone control (his caucus) so absolutely as he does," said Opposition Leader Tom Mulcair. "If he didn't want that to be discussed, it wouldn't be there."
"This is their backdoor way of signalling to their base that this is what they'd actually like to do and they just can't do it."
Mulcair said he won't have to whip his 100 MPs to vote against Woodworth's motion.
"I want to be very clear. We're not going to have to impose anything because our caucus is unanimous on this. We are unanimously opposed to that motion and that approach."
Interim Liberal leader Bob Rae said he's personally opposed to re-opening the abortion debate but Rae said he won't compel Liberal MPs to toe that line because the issue is a matter of individual conscience.
"If there are individuals in my caucus who feel strongly for moral reasons one way or the other, we're not going to whip the vote," Rae said.
Liberal prime ministers Jean Chretien and Paul Martin also had members of their caucus push to re-open the abortion discussion during their tenures.
Over 50 activists rallied on Parliament Hill Wednesday, one day before Woodworth's private member's motion will be debated in the House of Commons.
Julie Lalonde, a member of the pro-choice group Radical Handmaids, said she hopes their work will send Woodworth's motion "back to the hell hole it came from."
Woodworth says his motion does not propose any changes to existing law and simply sets out to discuss the current one. He said he hopes the motion is passed and that Parliament can have "respectful dialogue" about the "legal principles and evidence involved."