“If you are bitten by a venomous sea snake/krait, seek medical attention immediately. The National Poisons Centre also offers a 24/7 service on 0800 POISON.”
The creatures are non-resident in New Zealand waters and arrive on ocean currents more by accident than design, as the waters here are too cold for them to survive.
It is illegal to kill or harass a sea snake or to possess one, or part of one, without Wildlife Act authorisation.