> The result is black market of unregistered cigarette brands. A good number come across illegally from neighbouring countries. Perhaps NZ being an island nation might be able to control illegal imports better.
This is in the short term. This is also a slightly different situation, which is beyond the land-access. High taxes are an implicit indication it's still ok and for the wealthy, making it a status symbol. Banning cigarettes in NZ will put pressure on future generations to not start at all. This will not be 100% effective, granted for the next generation. From a cost-benefit perspective, if you are going to bring in black market products, why not get people started on meth? Meth has become quite prevalent in much of africa and partly because it's cheap.