A forensic psychiatrist testifying on behalf of the Crown says the shooting massacre at a Quebec City mosque was a racist act but not terrorism.

Gilles Chamberland says Alexandre Bissonnette didn't promote any type of ideology in carrying out actions that saw him kill six worshippers in January 2017.

He said today as Bissonnette's sentencing arguments ended that there were clearly racist overtones despite the killer's own assertions he was not Islamophobic.

Chamberland met with Bissonnette for four hours Wednesday and told Quebec Superior Court Justice Francois Huot it's difficult to assess the convicted killer's potential for rehabilitation.

Bissonnette, 28, pleaded guilty in March to six charges of first-degree murder and six of attempted murder related to the mosque shooting.

While his first-degree murder conviction carries an automatic life sentence with no chance of parole for 25 years, he can also receive consecutive sentences, which means he could spend up to 150 years in prison.