Be much more simple to put some long range tanks in and fly at 50' all the way across...no customs fees, no need to declare anything...and certainly going into NZ...no chance of interception
I do believe an enterprising young Aussie did this some years ago hiring an aircraft for a weekend trip away. He landed at a country strip to avoid making a declaration but got stymied when he couldn't get fuel for the return trip.
Much excitement when an eagle eyed local noticed the Aussie rego and the police turned up. Not sure what happened to pilot or aircraft.