A valuable source for many questions is Immigration New Zealand Operational Manual; the latest update was on 01 Apr 2011.
http://www.immigration.govt.nz/migra...al/default.htm
There are two options now:
1. online http://www.immigration.govt.nz/opsmanual/index.htm
2. pdf files (9 different files)
Individual titles are:
Administration, Temporary Entry, Border Entry, Compliance, Transit Visas, Refugees and Protection, Residence, Appendices & Glossary of Terms