Yes it is. All Airsoft guns are classified as firearms by NZ Firearms Law.
This means they must be:
- transported safely and out of site
- cannot be displayed in public
- you have to be 18 or older (of 16-17 with a firearms license) to be allowed to own, transport or sell them
While the law does not currently require Airsoft and Paintball guns to be stored in a firearms safe, reasonable security precautions are expected.