Ontario’s 6,000 jail guards and probation officers are threatening they could walk off the job Sunday morning to protest what they say are unsafe working conditions and unfair wages. But the deputy premier is warning that the province will take the steps “to address such misconduct.”

The jail workers are members of the Ontario Public Service Employees Union and have been without a contract since December, 2014. They will be in a legal strike position at 12:01 Sunday morning. If they walk off the job, managers from across the public service will be brought in to run jails and probation services.

Union negotiators returned to a Toronto hotel Friday morning in a last-ditch effort to try to hammer out a deal with the government. Tom O'Neill, the head of OPSEU’s corrections bargaining team, says they will keep talking past Friday if progress is made, but they are still going ahead with plans in the event they have to walk out.

OPSEU President Warren “Smokey” Thomas says he's concerned that the managers won't be able to handle the job within jails and ensure the safety of other staff there.

“Inside jails, I fear for safety of my members, I fear for safety of inmates who have mental health issues, many of whom are defenceless,” Thomas told CTV Toronto Friday morning.

The union said in a recent statement that the managers have not had enough training to take over, and “are in no way qualified to supervise the shrewd and violent criminals incarcerated in Ontario's jails.”

The union is also angry that replacement parole workers would be paid overtime at time-and-a-half and correctional facility workers would be paid double-time-and-a-half during any work stoppage.

If probation and parole officers walk off the job, Thomas said there could also be a risk to communities because parolees will fall through the cracks without proper supervision.

The union says Ontario probation and parole officers handle the highest caseloads in the country, and yet spending per offender is the second-lowest. Lethal weapons are regularly brought into parole offices, they say, but the government refuses to install metal detectors.

Thomas maintains there is a crisis in corrections and Ontario’s Treasury Board President Deb Matthews should come see what it’s like.

“If she could see first-hand conditions in jail, I’m quite convinced she’d have a change of heart because once you see it, I don’t believe anyone on this planet could be that heartless that you wouldn’t want to try to do something for these people,” he said.

Beyond the issue of safety conditions, jail workers also want to be deemed an essential service. That would mean their pay would rise with police and firefighters in binding arbitration, but would also mean they lose their right to strike.

Compensation is also an issue. Union members are angry that the province spent $58 million last year to top up managers' salaries, which had been frozen for years, but said there was no new money for wage increases for union members.

The last time the province's jail guards went on strike was in 2002. That work stoppage lasted 54 days, and there were riots at a number of correctional centres that resulted in broken windows and fires.

Thomas has said he has advised jail nurses, maintenance crews and kitchen staff -- who are covered under a different contract -- to not go into work if they feel unsafe.

In response, Matthews sent a letter back to the union saying that unified bargaining unit members, "are required to report to work and perform their duties in accordance with the terms and conditions of their employment during a labour disruption."

She added that the government "will take the steps necessary to address such misconduct" if workers don't show up for work, and they will address safety concerns through the Occupational Health and Safety Act.

But with the clock ticking on bargaining talks, the government has been making plans for a walkout by setting up trailers for manager to use as makeshift living quarters if they have to take over. As well, some managers have been clearing out offices and turning them into bedrooms.

With reports from CTV Toronto’s Naomi Parness and files from The Canadian Press