Brenton Tarrant, 28, appeared via a video link from Auckland Prison in for what was a quiet, ordered hearing.
The public gallery was packed to standing capacity with members of the Muslim community and journalists from New Zealand and around the world.
Armed police were outside as survivors and relatives of victims of the attack arrived at court.
Women in hijabs hugged one another as they arrived at the courtroom. Senior police officers, including Detective Inspectors Dave Lynch and Greg Murton, were seated in the front row of the public gallery.