I have a car on the water from Auckland to Port Kembla at the moment and am using Taurus Logisitics.
I haven't used them or anyone else from NZ before, but got quotes from 4 different companies online, and these guys were the most reasonable. The ship docks on Thursday and I should have the car by Monday, so can give you an update on my experience if you like?
Just be careful and read your quotes carefully, as when they quote you, the cheapest quotes are via Japan for some reason and the car will be on the water for 5 weeks. Ask for a direct quote, its about $500 more believe it or not, and only takes one week.
You also have the option of container or RoRo (Roll-on, Roll-Off) I opted for RoRo as it is only 1 week.