“In New Zealand there is no specific law proscribing nakedness in public. There are two sections of the Summary Offences Act 1981 to consider. First - obscene/indecent exposure (S27) and second, behaviour which may be offensive or disorderly (S4)
The first: S27, has been accepted as inappropriate for mere nudity because a lewd or lascivious element must be proved. Under S4, an appeal against a conviction of offensive behaviour has been allowed by the High Court, on the grounds that intent to offend (forensically), has to be proved.
A conviction for disorderly behaviour, though, has been upheld by the High Court, in a case where the nakedness was in a suburban street. (Not a place where the defence of it being: 'not uncommon' or 'known to occur,' applied.)
It is worth noting that the police's chief prosecutor in the Office of the Commissioner accepts that where the nakedness 'is known to occur' or 'is not uncommon,' it can be "said to be not illegal." (Unfortunately that hasn't stopped North Shore City writing a bylaw trying to say it is!)
In other words, having your gear off in the street is likely to get you a $100-$200 fine (if you either get a 'legitimate' complaint laid against you, or you ignore a policeman's warning). Otherwise, on a beach where 'everyone knows about it' you're fairly safe.“
Cit. from “Free Beaches New Zealand Inc.“ (freebeaches.org.nz) on 22 April 2019