Was just playing around with some dates and found this in August next year.
From: CHC/AKL
TO: AKL/CHC
Cost: from $22
Airline: Jetstar
Bags: not included
Example dates (all $22):
04 Aug - https://bookings.beatthatflight.com.au/flights/chc0408akl1
05 Aug - https://bookings.beatthatflight.com.au/flights/chc0508akl1
04 Aug - https://bookings.beatthatflight.com.au/flights/akl0408chc1
05 Aug - https://bookings.beatthatflight.com.au/flights/akl0508chc1
Presume more available, but I've not got enough time this morning to hunt :/