Lawyers for a man accused of killing six men at a mosque in Quebec City last January are appealing a lower court decision to have certain confidential documents made accessible to the media.

In a motion filed earlier this week, lawyers for Alexandre Bissonnette say the Quebec court judge committed an error in law in allowing the documents released.

Bissonnette, 27, faces six counts of first-degree murder and six of attempted murder using a restricted firearm.

Prosecutors filed a preferred indictment against Bissonnette and say they are ready to set a trial date on Dec. 11

A consortium of seven media organizations including Radio-Canada, Montreal La Presse and TVA had asked the court to remove the seal on 10 search warrants carried out between Jan. 30 and Feb. 6.

They received part of the documents in mid-October after Judge Alain Morand ruled they were in the public interest, but the rest remained sealed to allow for an appeal.

"The publication of this information would cause real, serious, significant and irreparable harm to the fairness of the trial, and the adverse effects are greater than the beneficial effects on the right to freedom of expression and the public's right to information," defence lawyers Charles-Olivier Gosselin and Jean-Claude Gingras wrote.

Arguments are expected to be heard on Friday.