Depending on the level of education you are in. For something proper at Tertiary level, on this below is comprehensive and assessment fair.
However, it gets tricky for Secondary students and language students. The former are mostly not even adults and therefore they would face an additional set of challenges. The need of having some sort of dependant bonds with others is still strong at that age, and I have seen it break or make someone depending what sort of relationships they strike up with others. Many would feel lonely and isolated, reverting back to sticking with their own kinds or have behaviour issues. Those with family/ relative/ a good home stay environment tend to fare better in general although nothing is absolute.
Therefore to the parents wanting to send their young kids over to NZ, I do have some word of warning. Although NZ in general is safe, you are still exposing your kids to a lot of risk. By a lot, I mean, life and death type of a lot. Stories of quiet kid getting up to no good is rampant. The industry responsible for bringing in international students is rather competitive amongst themselves and as a result not all of them are honest and responsible.
For language students it may be also tough, too. In a town with just a few foreigners trying to speak English with the locals might be still novelties for the residents, but when you mix a huge number of language students, people get less patient with you..etc. Places like Auckland can be really bad, you don’t even need English to live in some places. (I am an Asian in Wellington, and people are speaking English with me all the time. However, when I go to Auckland, sometimes people would be reluctant to approach me because they don’t know whether I speak english or not. It is rather annoying for me but I don’t blame the locals. )
While I agree it is important to encourage international students to mix with the local and observe Kiwi customs, it is very difficult for Secondary and language students to do so.