A coronial hearing into the Christchurch Mosque attacks has begun, but it's not a question of who is to blame.

Coroner Brigitte Windley is tasked with determining the circumstances of each of the 51 deaths - and addressing unanswered questions.

It follows a criminal prosecution and a Royal Commission of Inquiry.

Herald senior reporter Anna Leask has spent the day in court- and she says the Coroner is clear the responsibility rests on terrorist Brenton Tarrant.

She says this is about shining a light on what happened.

"Tarrant didn't go to trial because he pleaded guilty and the Royal Commission was done more privately, so there's a lot of the evidence that the families of the victims will only hear during this process."

LISTEN ABOVE

• ‘Could they have been saved?’ - Inquest into Christchurch terror attack begins as families ask for answers
• 'Imprints of the attack are still strong' says researcher on Christchurch terror attack
• Chch mosque terrorist pleaded guilty under ‘duress’, considering appeal - new lawyer
• Coronial inquiry launched into Christchurch mosque shootings