Imagine you have a toy that you think is the coolest toy ever, but none of your friends have ever heard of it. You might tell them all about it and try to convince them to love it too.
That’s basically what “world famous in New Zealand” means. It’s when something is really popular or well-known in New Zealand, but not necessarily famous around the world.
People in New Zealand are really proud of their country and sometimes like to say that things are “world famous in New Zealand” as a way to boost their own country and make it seem more important.
It’s kind of like how you might brag about something cool in your town or neighborhood to try to show that you’re a part of something special.