The price of prison tobacco is expected to skyrocket when a blanket smoking ban in federal prisons takes hold next month, says a former con who served 14 years for murder.

"It will create a black market. Tobacco is more expensive than any other drug you can buy in prison. A bail of tobacco (small pouch of loose tobacco) that normally costs about $16 is about $300 in jail. If you roll it and sell the cigarettes, you can get $500," said Glenn Flett.

Flett, 57, is the founder of Long Term Inmates Now in the Community (LINC) - a Vancouver-based program helping ex-cons stay straight.

"Tobacco already causes violence. Banning it outright is going to create some pretty big problems and general unrest," he said.

An indoor smoking ban started at Correctional Service Canada facilities in 2006. The new ban outlaws smoking outdoors.

Kevin Grabowsky, regional president of the federal guards union, wants shifts at the maximum-security Edmonton Institution to be bolstered in case of any initial resistance to the ban.

It comes into effect May 5.

"We're going to have groups of inmates that are probably going to be resistant to it," Grabowsky said.

"We've had intelligence that the price could go up to $1,000 per bail. Somebody is going to want to run the tobacco trade just like the drug trade ... you can get somebody severely hurt and or killed in prison for a couple of bails of tobacco."

Correctional Service Canada is supporting the ban by providing inmates with access to smoking cessation programs.