I just went through NZ a couple of days ago. The entry declaration form is much more comprehensive than for other countries and has had several questions added recently, along with a warning that there is a fine for any wrong declaration with no recourse (something like NZD 400 on the spot fine). That would include failing to mention that you are carrying restricted medications (which are all the things mentioned on this thread). Enforcement is by profiling as well as random checks. In general any medication with a doctor's prescription is allowed entry, just be sure to have a valid and current prescription form with you (the label on the bottle is not it
).