PRISONERS in South Australia have been put on notice their smoking days are numbered, with smoking banned indoors by 2015.

The Government, however, has warned there are "particular challenges in restricting smoking in the state's prisons" and says a total smoking ban still is some time away.

New Zealand jails will go smoke-free in July in radical laws designed to make prisons healthier. To prepare addicted prisoners in the lead-up, the NZ Department of Corrections is trialling a bizarre national directive to supply inmates with two carrot sticks a day.

NZ prisons stopped selling cigarettes last week and, as of July 1, all tobacco products will become nationally prohibited items, or contraband.

Most of the country's 5700 smoking prisoners have been using nicotine patches for the past year in preparation for the move.

The ban, announced last June, has been hotly debated, with many believing it curbs prisoners' civil rights, takes away their only pleasure and will increase the risk of rioting and violence.

In Adelaide, Health Minister John Hill said the Government would be working with prisons to develop smoke-free policies.

He said it would be encouraging new facilities to be smoke-free indoors and for established prisons to "move towards this goal in the longer term".

Correctional Services chief executive Peter Severin said about 80 per cent of prisoners in SA smoked and the department was looking at "stopping smoking, full stop".

"It would be a very brave man who introduced a total smoking ban immediately," he said. "We will be keeping a close eye on how the NZ plan works.

"Our commitment is to see no smoking indoors by March, 2015. Already, smoking indoors at Mobilong prison is banned."

Mr Severin said introducing the indoor ban would be harder at facilities such as the Adelaide Remand Centre, which did not have any outdoor areas.

"We have to have provisions to enable prisoners to wean themselves off smoking," Mr Severin said.

Mr Severin said the department also had to take into account the issues of prisoners' civil rights before enforcing a total ban.