A labour dispute involving hundreds of prison guards in Alberta appears to be gaining momentum as it enters day three. Sheriffs have now joined the wildcat strike, according to the worker’s union.

The Alberta Union of Provincial Employees announced Sunday that provincial sheriffs in Edmonton and Calgary “voted overwhelmingly” to support the striking guards.

The sheriffs patrol highways and provide security in courthouses, a union spokesperson said.

Despite the union announcement, the province said the number of pickets on Sunday had dropped and many guards across the province have returned to work.

The province’s Labour Relations Board issued a cease and desist order on Saturday after the strike was declared illegal. Corrections staff ignored the order requiring them to return to work.

The government released a statement Sunday explaining that the province wants to help guards return to work.

"Some of you have returned to work, and others have said they would like to return to work but feel intimidated,” the statement said. “We are aware of these union pressure tactics, which include misinformation being distributed.”

A spokesman for the province's justice minister said staff at 10 detention centres throughout the province have been issued the cease and desist order.

Guards at the Edmonton Remand Centre walked off the job on Friday after an employee was suspended for complaining about safety issues at the newly-built mega-jail.

News of the walkout quickly spread to other Alberta correction facilities, with workers joining in the wildcat strike.

Guy Smith, president of AUPE, said employees are vowing to continue the strike until their safety concerns are addressed.

Guards have since been replaced by police and RCMP officers and correctional supervisors and inmates have been restricted to their cells.

The AUPE claims that it had found five pages worth of design flaws after touring the sprawling facility, which will eventually hold up to 2,000 inmates.

The union also said it was not satisfied with some of the new procedures implemented at the mega-jail.

Inmates began moving into the north Edmonton centre on April 12, but a union spokesperson said concerns were raised well before the opening.

With files from The Canadian Press