That has been one of the first questions I asked myself. What do I need to know? Law and rules?! I got an realy easy and quick solution for you. I highly recommend the following video and website. But take care. Please read the disclaimer at the bottom of the linked page. It is realy important that you know its not the 100% solution. Everyone who fly drones know there are always problems. That is the closest solution for amateur pilots.
Here is the website by airshare.co.nz – there you can see the map of NZ only about flying drone. Please read the disclaimer!