Commuters in York Region will have transit strikes to contend with Monday morning but those depending on GO Transit can breathe a sigh of relief.

Hundreds of drivers and maintenance personnel with Miller Transit, First Transit and Viva will walk off the job at 4 a.m. but union workers employed by GO (Metrolinx) came to a tentative agreement at around 10 p.m., just two hours before the midnight bargaining deadline.

GO workers will vote on the new agreement later this week to ratify the deal but commuters can expect regular service Monday morning.

Approx 40,000 commuters use GO buses every day.

Miller Transit is contracted to serve 51 York Region Transit routes in Markham, Richmond Hill and Vaughan while First Transit operates 29 York Regional Transit routes in the northern part of the region. Both groups are represented by Amalgamated Transit Union 1587. All told about 340 employees are affected.

About 220 VIVA drivers will also walk off the job, shuttering service on five express routes. The VIVA drivers are represented by Amalgamated Transit Union Local 113.

The three groups account for about 60 per cent of the entire transit service for York Region.

For a list of all affected routes, click here.

"We regret the inconvenience this causes for York Region transit users and we urge them to contact their councilors and mayors," ATU Local 1587 President Ray Doyle said in a press release announcing the strike. "The politicians are the ones who are ultimately responsible for this mess and they are the ones who must fix it."

"These employees are just asking for enough to minimally close the gap and ensure that they are compensated fairly," added ATU Local 113 President Bob Kinnear.

Negotiations between ATU Local 587, ATU Local 113 and Miller Transit, First Student Canada and VIVA have not been held since both unions rejected an offer from their employers Thursday.

According to Doyle, the main issues of contention revolve around pay and benefits in comparison to other transit operators.

"These private companies are raking in profits by the millions from taxpayers and passengers, while paying their employees seven dollars an hour less than transit workers doing the same jobs in adjoining cities," he said. "This is not a sustainable situation."

York Regional Transit General Manager Rick Leary told CP24 that he is hopeful a settlement will be reached sooner rather than later, but he advised commuters to "prepare for the worst" in the interim.

He said YRT will have attendants at many major bus stops in the morning to advise commuters on transit alternatives and said people should consider car-pooling, using Go trains or taking one of the 13 TTC routes which run through York Region.

The last time a strike affected YRT routes was in 2008 and it lasted two weeks.

"We are made up of four different transit providers and the issue is between the contractors and their union," Leary said.