It has been a month since prisoners could purchase cigarettes.
And from last Friday, they were no longer allowed to smoke at all.
All tobacco products, and the means of lighting them, are now completely banned from New Zealand prisons.
Some people predicted riots and a black market in tobacco.
But has either of these things happened?
Natasha Utting visited the prison which had the highest number of smokers in the country, to see how they are coping without cigarettes.
Watch the full video.
3 News