http://www.acc.co.nz/about-acc/overview-of-acc/how-were-funded/index.htm
It's funded by taxes that come from wages, payroll, petrol taxes and vehicle licensing taxes. It's divided into 5 categories depending upon whether the accident happened at work, on the roads, to a wage earner, to a non wage earner, or due to "Treatment Injuries" which used to be called "Medical Misadventure."
When someone comes in to see their GP with an ACC injury, an electronic form is filled out with all the details of the injury, where it occurred, etc. This is electronically filed with the ACC. The ACC then covers the cost of the doctor visits, medical imaging, hospitalization, visits to the specialists (they're seen within the private system so they get seen faster), and covers lost wages for those who can't work and can also cover additional help that is needed at home for care etc.
It is fully funded each year for all the anticipated future costs of each injury. Since some injuries are permanent and someone may lose 30 years of employment, the money for this is set aside now and invested so that it's covered and future generations aren't stuck with the cost of an injury that happened many years before.
There is an incredible amount of data generated regarding the injuries, where they occurred, etc. You'll see billboards on bus stops saying "41,232 New Zealanders slipped and fell in the bathroom and injured themselves last year." with information on what you can do to decrease your risk of injury. Bike helmets are required for anyone riding their bike, seatbelt use is mandatory, and it's against the law to talk on a cellphone or text while driving.
The other interesting offshoot is in medical malpractice. Since any injury caused by "Treatment Injuries" is automatically covered, one doesn't have to sue their physician and demonstrate negligence to recover damages. Thus one is automatically cared for without cost, your income is covered if necessary, and there is no need to resort to litigation. It is extremely rare for physicians to get sued here for medical malpractice. Therefore, my medical malpractice insurance is $1200 per year as opposed to about $14,000 a year in the states. Of course there is still a complaint system in place for patients that have complaints about the care they've received. Each of these complaints is reviewed by the proper medical board and there's a separate disciplinary system that is available if necessary.
My medical malpractice carrier also covers physicians in the UK and many other countries. They send out a regular mailer talking about cases and damages, etc. They regularly talk about what a great system the ACC is and how it would be a vast improvement if adopted in the other countries they operate in.
