More than 1.75 million people indicated yes on their licence - 52.7 per cent of licence holders - and there were 36 deceased organ donors in New Zealand last year.
Historically, most donations were from people who suffered brain injuries in a vehicle accident, but safety education had resulted in several hundred fewer deaths, Dr Streat said.
Now most donors died from spontaneous bleeding in the brain from a ruptured blood vessel, but fewer smokers and better treatment meant fewer deaths and donors.
About 30,000 people died annually in New Zealand but fewer than 100 people died under circumstances allowing organ donation.
"You need to die in an intensive care unit, as a result of a severe brain injury and be on a ventilator."
A dead person's family could decline to donate. About half of the families of eligible donors accepted.