Hello, Steven -
Are you asking for the telephone number for the New Zealand Inland Revenue Department?
I am answering from the USA.
This is the link to the New Zealand Inland Revenue home page:
If you need to know an IRD telephone number, choose the Contact Us link in the upper right corner of the home page.
Are you asking to know your own Inland Revenue number? I cannot provide that to you. You will need to contact New Zealand Inland Revenue Department directly.
Note: Fixya.com is a website for asking and answering questions about how to repair _things_. I chose to answer your question because I am a librarian by profession. By the way, I am sure a librarian at the public library nearest you in Australia could have easily helped you with this.