The short .NZ domain name is simple to use and easy to remember. It was released on 30 September 2014 and amongst the other NZ domain extensions is the newest. The chances that you can still register your favourite domain name are high.
A good option is to register the shorter .nz domain name if your favourite third level domain eg. yourname.co.nz is already taken. If you already have a third level domain you should consider registering the shorter version as well to increase your visibility and to protect your brand name.