AKL - HKG flights in the "Economy Saver" buckets (T, W, V, Q the usual suspects) earns you around AP$42-46, and goes for around $1600-$1800 return on any given day.

Which means (taking the lower earn here) ~AP$84 return. In order to redeem a reward, you'd need $1600/AP$84 = 19-20 return flights.

Of course NZ does deep-discount specials to HKG, with the cheapest being around $1000 return on Grab-a-Seat deals. That still means ~12 return flights needed just to get an award flight.

NZ is utterly terrible in terms of mid/long-haul burn. Most on here knows that already.

Comparing the above, QF is "easier" to get an award flight.