Kia ora Jj. I live in this region and we are fortunate to have a highly experienced and qualified natural builder here. His name is Matt Cassells, and he is one of the instructors in our
PDC (we're co-teaching
energy and tech
online this weekend). He's done rammed earth,
cob, light
straw, and many other variants of construction, including restoration work on some historic cob structures in the South Island. I can put you in touch with him if you like.
There are earth building standards which have been adopted in the Building Standards Code, and
EBANZ has been instrumental in making this happen. Since the main types are in the code, councils have to use that as their guidance (although some councils are better than others when it comes to cluefulness among their planners and inspectors).