A NZ CAA Medical Certificate Class 1. You can apply for the course without a Class 1 Medical Certificate. If you are accepted onto the course your commencement of the course will depend on you gaining a Class 1. If you are an international student, you can apply and be accepted without a medical certificate also, again your course commencement will depend on whether or not you hold a class 1. Some countries have services that provide a NZ Class 1 Medical Certificate.
You can find this information on the CAA website; https://www.caa.govt.nz/script/directory-of-overseas-medical-examiners/ If you cannot gain a medical certificate in your home country you can wait until you arrive in NZ. If you get here and can’t obtain a medical certificate then you won’t be able to commence the course and you will have to go home. Immigration New Zealand is advised if this happens.