Not so good at this:
https://www.google.com/flights#flt=S...D;e:1;sd:1;t:f
Looks like needs to be longer stay. Found to all kinds of New Zealand destinations. Mostly looking early 2019 but flights in Nov and Dec also. Not showing up on ITA but easy to find on Qantas website. Seems like 14 day is needed for lowest fare.