Justice Minister Peter MacKay says newly-introduced not criminally responsible legislation seeks to establish clear lines between offenders who are at a high-risk of re-offending, and those who are not.

The bill, introduced Monday, creates a high-risk designation that would keep some offenders in custody even if they've been deemed by a court to have a mental illness that prevents them from being convicted of a crime.

"We're not talking about keeping individuals behind bars.  They're not in the classic corrections system," MacKay told CTV's Canada AM on Tuesday. "They're actually in secure medical facilities where they can receive treatment.”

He said the number of not criminally responsible (NCR) offenders who would be placed in the high-risk category would be "very low."

The contentious bill has received some opposition from lawyers and mental-health professionals.

In a statement to CTV News, Schizophrenia Canada said it's hoping the government will work with health organizations to make amendments to the bill that "support all victims of crime as well as victims of untreated mental illness in reducing the stigma and discrimination associated with mental illness."

However, MacKay said the creation of a high-risk designation could help deal with the issue of stigmatization by clearly defining NCR offenders who are "not a risk to the public."

"It provides clarity and public confidence and it puts clear lines in place between those who are a risk and those who are not."

MacKay said protecting the public is the primary consideration of the bill and putting victims of crimes "front and centre in the system" is also a priority.

The legislation would require the justice system to notify victims when an NCR offender is released from custody.

He said the public has raised concerns about a number of high-profile cases involving NCR offenders. 

Vincent Li – an undiagnosed schizophrenic – was found not criminally responsible for beheading a passenger on a Greyhound bus in 2008. Li was granted permission last spring to leave the mental-health centre where he is being held on escorted day trips. 

Experts working with Li have said he is at a low risk to reoffend.

"In those facilities it is, in my estimations, best left to the hands of the professionals before making the assessment to put a man like a Vincent Li back in the community where there is any possibility of reoffending," MacKay said.