The Appeal Court justices are hearing a joint set of six appeals, each of which involves mandatory minimum sentences for gun crimes.
The arguments focus on the three-year mandatory minimum sentence for possessing a loaded prohibited gun — a law enacted in 2008 as part of the federal Conservatives`omnibus crime bill.
The mandatory minimums were struck down in one case and upheld in the rest and hearing all of them at the same time gives the court the opportunity to send a uniform message.
Justice David Doherty — one of the judges hearing the appeals — has suggested he considers a law that sends first offenders to prison for three years on a gun possession crime a "bad law."
Lawyers for both the federal and Ontario governments have raised the issue of recent gun violence in Toronto as they argued in support of the mandatory minimums.
Several organizations are also intervening in the cases.
The African Canadian Legal Clinic argued Wednesday that the law will have a "grave impact" on the black community.
Longer sentences will perpetuate the disadvantages people in the community already face, the clinic's lawyer argued.