The nearly 80 per cent of New South Wales inmates who currently smoke will be forced to quit when the state introduces a smoking ban in jails in August next year.

About 8,000 inmates smoke and prison officers are also currently permitted to smoke at work.

Both will have to give up when the ban is introduced.

NSW Attorney-General and Minister for Justice Brad Hazzard said Quit programs and nicotine replacement therapies would be offered to inmates and prison officers alike.

"It's a clear undertaking that's going to improve the health of 10,500 throughout the system," he said.

"The message from other jurisdictions who have introduced smoking bans is work constructively with inmates, work constructively with staff and make sure there are the programs to support them."

Mr Hazzard said in other jurisdictions many prisoners have used it as an opportunity to quit.

"Interestingly the experience has been that a lot of inmates give up voluntarily," Mr Hazzard said.

The chair of the Prison Officers' Association, Steve McMahon, said it had taken a long time to happen and his members had hoped for a ban to be introduced early last year.

Mr McMahon said the concern now was the possibility of a backlash from prisoners.

Former prisoner and Justice Action coordinator Brett Collins has told the ABC that forcing a ban on smoking will cause problems in NSW jails.

"Smoking is central to the life of prisoners," he said.

"It's sold in every canteen, it's currency, it's part of the culture in prisons.

"This decision is symbolic of disrespect. It will cause trauma."

But Cancer Council NSW's Tobacco Control Unit manager Scott Walsberger said it was a move in the right direction.

"Prisons are one of the last indoor workplaces to go smoke-free, so this is a huge leap forward," he said.

Mr Hazzard said quit smoking treatments would be offered along with face-to-face counselling to help inmates and staff give up smoking.

There would also be behaviour management training and and more exercise programs on offer.

However, from August 2015 tobacco will be treated as contraband in all jails.