NZD500
Coupon code is automatically applied, basically $500 off return economy flights to anywhere in North America using NZD500, there is also $1000 off premium economy & business using NZD1000.
Best prices I found after discount were high $1300s or low $1400s, obviously it varies depending on date and location, not a lot of great prices but a few that seem decent and you might spot something. Worth a quick look.
For travel between 1 May - 25 June, 20 July - 14 September & 19 October - 30 November 2015.