I had recollections of it being a non stop 737 service in the '90s so dug out some of my old timetables to look.
I can't find my earlier ones but looking at the 1995 and 1996 timetables there were 2 x daily 737 services NZ416 and NZ530 with NZ416 stopping at WLG on the way and NZ530 stopping at CHC.