To study at NSIA as an international student you must have a current student visa for a specific course within the school.
From 1st October 2019, you are not able to travel into New Zealand without a visa or NZeTA (Electronic Travel Authority). See here for more information https://www.immigration.govt.nz/new-zealand-visas/apply-for-a-visa/about-visa/nzeta
Student visa applications can be lodged via your agent or through the NSIA online visa application system (this system is only applicable to students who are already in New Zealand).
Upon arrival in New Zealand, the school will check your visa for validity and a copy is kept for evidence on your personal file.
If you are found to not hold a valid visa or you terminate your enrolment prior to commencement of your course, Immigration New Zealand will be notified immediately.
Full details of visa and permit requirements, advice on rights to employment in New Zealand while studying, and reporting requirements are available through Immigration New Zealand, and can be viewed on their website.