Take a look at this article from Xero about your NZBN business number. Makes good administration sense.
“Right now every company registered in New Zealand has an NZBN. By the end of the year business numbers will be allocated to other kinds of businesses including sole traders, charities, and partnerships. The NZBN will streamline all essential business information, and over time will become the only number businesses will need to use to interact with each other, the government, and its agencies. Eventually it will replace other numbers and each entity will only need to use their NZBN as their main identifier.”
Read the whole article here.