When I try to reproject this to NZTM2000 using the Project Raster tool, I can select the source and destiniation coordinate systems, but there is no transformation that is appropriate (only the reverse one exists in ArcGIS) and, although transformation is 'optional', an error message appears that it's needed when I try to reporoject without specifying a transformation.
I have two problems:
1. ArcGIS doesn't have a built-in transformation between WGS84 and NZTM2000. It only has the reverse - NZTM2000 to WGS84.