You need good English language skills in New Zealand. Employers require it, and Kiwis generally assume everyone will be fluent in it.
You may have learned some English in your home country. That’s great, but you may still find understanding us, and being understood yourself, hard to start with. We use a lot of slang you won’t be familiar with and we tend to talk very fast.
If you don’t understand what’s being said to you, make sure you let people know. And ask them to slow down and to explain the Kiwi slang words and phrases they’re using.
There are English language courses to suit all styles and levels of English, so check out your options and get started as soon as you can.