Public law specialist Mai Chen says the purpose of the Royal Commission into February's earthquake in Christchurch is to investigate what happened, not to incriminate.
Terms of reference issued on Monday mean the Royal Commission will not consider who is to blame for the building failures.
Some of those affected by the earthquake are questioning why a Royal Commission is taking place if parties culpable for building collapses will not be held liable.
But Ms Chen told Morning Report the provisions concerning no liability and the terms of reference for the Royal Commission are quite common.
She said separate investigations will have to be made if the police or other agencies want to prosecute.
The Royal Commission will focus on buildings that fell within the Four Avenues area.
CTV, which lost 16 people, is questioning why an inquiry is being held if culpable parties are not going to be held responsible.
Ann Bodkin, who was trapped in the collapsed Pyne Gould Corporation building for 25 hours, also thinks liability must be addressed.
A spokesperson for the Attorney-General says Royal Commissions do not function as a court of law.
The number of people named as killed in the quake is 172.