New Zealand Amateurs who hold a current NZ General Amateur Operators Certificate are able to operate under reciprocal agreements in many countries around the world.
The majority of these are by virtue of the the European Conference of Postal & Telecommunications Administrations ( CEPT) agreements.
Generally the website for the Amateur Radio body in the country you are visiting will have specific details of any requirements.
These links are to visitor information of the more frequently visited countries by ZL hams:
For almost all other CEPT countries The ARRL publish an excellent list of Reciperocal agreement information here:
Last Updated: 05 March 2020