A comprehensive cessation programme must be available to prisoners if smoking is banned in jails, the Rethinking Crime and Punishment group says.
The Government is reportedly looking at making prisons smokefree from next year, with Corrections Minister Judith Collins expected to make an announcement early this week.
The Corrections Departmentis concerned taxpayers could be liable for legal action from prison officers exposed to inmates' second-hand smoke and also the potential threat of lawsuits from nonsmoking prisoners, bunking with prisoners who do smoke.
Corrections Association president Beven Hanlon told Radio New Zealand prisoners did not like change.
"People coming off nicotine can be very unpredictable, can be very anxious, aggressive and we're going to have a large part of our prison population going through that and we're (prison officers) going to have to manage them," he said.
Rethinking Crime and Punishment director Kim Workman said it would be particularly difficult for new prisoners who were already grappling with drug and alcohol withdrawal, and mental and physical health issues.
He said the move was likely to cause "violence or mayhem of some kind".
A black market in tobacco was also likely, he said.
Prime Minister John Key said he supported banning smoking in prisons which had been done successfully in Australia.
There would need to be programmes to help prisoners quit, he said.
"I think it takes a period of time, I think it's quite cold turkey actually... eventually there'll be a day that they say that's it, they're smokefree and we'll go from there."
Prisoners would have access to quitting programmes, he said.
The impact of secondhand smoke on corrections staff and nonsmoking prisoners was one factor in the decision.
The were other issues such as prisoners trading cigarettes and having access to matches and lighters, Mr Key said.
