The Auditor General will be investigating the effectiveness of the firearm buy-back scheme.
The government watchdog decided it would add the scheme to its work programme, due to the significant public interest.
It will focus on how well scheme met its objective to get as many firearms covered by the ban out of the community, as quickly as possible.
It was also look at the safety and ease for people attending events, whether the costs are accurately accounted for and the New Zealand Police's reporting of the scheme.
The Auditor General will report back its findings to Parliament early next year.