Studying in New Zealand is very expensive. It is also perfect. Courses in the science areas of study and engineering as well can cost from $25,000 on up (New Zealand money). Medicine and dentist studies are even more expensive, ranging from New Zealand currency - $75,000 (£36,300) and even higher. For fields such as exclusive fields of study like specific categories within the medical field, like being a heart surgeon that requires even more years of study than being a regular physician does.
Still, it's a fantastic place to live and study and the education there is excellent as well. If you have the money to go and study there, do so. But, you'll have to figure in living expenses too, and they aren't cheap. If you happen to earn a scholarship to study in New Zealand, you are one of the fortunate as they are not given freely but are priceless.