You will see here
https://www.immigration.govt.nz/new-...-visa#criteria the full criteria for obtaining a student visa, and they include having the offer of a place on a suitable course. Therefore, that will be the first necessity, even before knowing that an INZ office is open and accepting applications again. And I don't suppose that the universities and other education course providers will be making any offers to overseas students until the NZ government decides to reopen the borders, which the Prime Minister has said will not be done any time soon.