Are you on some type of a waiting list in case there are cancellations?
No, there's nothing like that.
If a person cancels, the next person on the list gets the surgery. So, if you're number 22 on the list and number 21 cancels, it's your turn. If you're number 23, you move up to 22 - and the person who was number 21, but who cancelled, goes back to the end of the list, so he/she could go to number 100+.
Since you might only get a few days' notice of your surgery date, you don'tr want to go away to anywhere you can't be contacted, or you could miss your turn.
For a health care system that's supposed to be all about providing the best possible care at the least possible cost, it's mind boggling how they can do so much duplicate work
"At the least possible cost:" is the over-riding factor - not for the patient, but for the Health Board.
While the NZ NHS provides free treatment, it is chronically under-funded. The money to pay for it comes from our income tax and a certain amount is then allocated to the District Health Boards (DHB), of which there are 20 in NZ.
Each DHB is allocated a certain amount each year, with which it has to provide health services and attempt to stay within budget. There's never enough money to provide all services, so each DHB has to find a way to deny what it considers to be non-essential services. That's why patients have to be assessed according to a points system for their need for surgery.
Everyone is treated in an emergency, but there are seldom enough funds for some routine surgeries. For example, if you have a hernia and it strangulates, you will be given an emergency operation and excellent care. But if you have a simple hernia that causes no problems, you will not get surgery, unless you pay for it privately.