The Quebec government reversed a decision Friday to ban prisoners from smoking outside, hours after a riot at one of the provincial detention centres.

Provincial Public Security Minister Jacques Dupuis announced the decision, which went into immediate effect Friday morning.

"This is a decison that I took last Monday. The inmates will be allowed to smoke outside on the exterior land of the jail," he said. Dupuis added that if the general population can step outside for a smoke, prisoners should be allowed to as well.

His announcement came a few days after the government first implemented the unpopular ban on smoking both inside and outside prisons. Smoking inside is still not allowed.

Prisoners' rights groups predicted the ban would anger inmates and lead to more tension with guards.

Jean-Claude Bernheim said 80 per cent of inmates smoke, and that forcing them to quit cold turkey would lead to more violence.

"We know everybody who stops smoking has a bad physiological reaction and psychological reaction," he told CTV Montreal.

Late Thursday, as many as 70 inmates set fire to their cells in a wing of Quebec's Orsainville jail, presumably in response to the smoking ban, prompting police to surround the detention centre.

Dupuis denied Friday's announcement was a political flip-flop, and said the decision was not a response to the riot.

The ban, which was introduced Tuesday, was meant to follow the lead of federal prisons. Dupuis said he was working on easing the rules even before it was implemented.

When the ban was first announced, the government said prisoners themselves would have to pay for nicotine patches if they wanted to ease cravings.

Later, the provincial government said it would cover the costs under a full ban.

Quebec was believed to be the last province where inmates still held on to the right to light up.

With a report from CTV Montreal's Rob Lurie