Almost everywhere in Christchurch! Generally good prices. Be careful of how much a day pass is because the machine will allow you to pay more if you're not careful. Generally full day is 4-5x hourly rate - at least for Wilson park in front of the hospital.
I had to call them once because I was not able to understand how the nightly price of the parking was working. I had to wait a bit before being able to reach an agent but the person I got was very friendly and answered quickly to my questions.