TORONTO -- Ontario's correctional workers have given up their right to strike in the latest round of contract negotiations with the government.

The Ontario Public Service Employees Union and the government reached an agreement early Saturday morning after a meeting with a mediator.

As part of the negotiations, the union says corrections workers have been declared an "essential service," meaning they will no longer have the right to strike, and future bargaining disputes will be determined by binding arbitration.

The workers, including 6,000 jail guards and probation officers, had threatened to go on strike on Sunday if a deal had not been reached.

The union had hoped that correctional workers' salaries would increase to match those of first responders like firefighters and police officers when they gave up their right to strike, but this agreement doesn't touch on wages. That issue will be determined by an arbitrator in the coming months.

The workers, whose last contract expired in 2014, rejected a previous tentative agreement.

Another part of the deal is a commitment to lift a long-standing hiring freeze and hire at least 25 new probation and parole officers.

Thomas said this development is "huge," although the union originally wanted 100 new probation officers, and hundreds more corrections officers and jail guards.

He added the province has not agreed to hire a specific number of corrections officers.

"Of course we would have liked a lot more, but we took what we could from the employer," said Tom O'Neill, chair of the correctional bargaining team.

"It didn't happen overnight, and it's not going to be cured overnight, but we're definitely moving in the right direction.'

The government said the settlement is consistent with its fiscal plan and will not increase the deficit.