This seems appropriate on Xmas Day as it might result in a great Christmas present for you (if you don't already have it) (If it's been raised before, I apologise...) (etc...). I recently discovered it, and while I'm using it on flights around Europe at the moment, I think it will work equally well in NZ.
It's called AIG AI Manager, and it's an absolutely brilliant piece of traffic software for P3D (and FSX), and it's FREE. I used to use MyTraffic6 but could no longer stand the luminous, pixelated planes, so looked for something else.
With AIG (no relation to the insurance company as far as I'm aware), you choose airlines, then download each one's schedule and aircraft, so here you could download Air NZ, Qantas, Emirates, Jetstar etc. You need to adjust your traffic settings in P3D to whatever you want (I'm on 70%), and delete the rubbish default planes in the sim objects folder. The planes you get are lovely to behold and don't seem at all heavy on framerates. They take off and land very convincingly, with spoilers, and the puff of smoke as they touch down. They use real world schedules at each airport. It's unreal (yet realistic).
Installation isn't hard, - they have a 'one-click installer', or OCI, although I couldn't work out which click the one was amongst the plethora that you have to do. There's a pdf tutorial, which is rather dry, but I found a video on YouTube, which worked better for me.
70% might be slightly high because I'm getting rather a lot of conflicts on my TCAS, but I figure they're smart enough to avoid me. I just love seeing airports populated with lots of appropriate planes.
You can find it here: