Justice Minister Peter MacKay introduced legislation Wednesday to eliminate parole for those convicted of first-degree murder involving sexual assault, kidnapping, terrorism or the killing of a public officer, or in a particularly brutal killing.

Prime Minister Stephen Harper previewed the "Life Means Life Act" earlier this month, saying it would only apply to "a relatively small number of offenders."

Currently, those who are convicted of first-degree murder face an automatic sentence of life in prison with no chance of parole for 25 years.

On Wednesday, MacKay introduced the bill for first reading in the House of Commons, saying "offenders need to be subject to penalties that fit the severity of the crimes." 

Bill C-53 ensures the most violent offenders "take their last breath behind bars," MacKay added.

Mulcair calls bill 'playing politics'

The minister criticized the Liberals and the NDP for voting against Conservative crime measures.

NDP Leader Thomas Mulcair accused Harper of digging for ways to separate the Conservatives from the opposition.

"This applies to so few people and judges already have the power to declare someone a dangerous offender," Mulcair said, "This is more about Stephen Harper playing politics than it is any real issue."

It will be difficult to pass the legislation through Parliament in the 11 weeks remaining in the parliamentary calendar as the bill needs to be debated in the House and Senate, plus examined by two parliamentary committees.