The union representing Ontario's English Catholic teachers warned its members on Wednesday of a possible strike this fall.

The Ontario English Catholic Teachers' Association (OECTA) says negotiations at the bargaining table have so far been "lengthy and complicated," and as a result, a strike or work-to-rule action could take place when students return to school after the summer break.

"It's highly probable that the Association will need to take strike action in the fall if we do not make progress at the bargaining table," OECTA president James Ryan said in a letter.

The letter was emailed to union members on Wednesday, CTV Toronto's Naomi Parness reports.

The OECTA represents approximately 50,000 Catholic teachers across Ontario.

Wednesday's news comes after members gave their union a 94 per cent strike mandate in April.

Ryan said the April strike vote was a sign that teachers are pushing back against the provincial government’s "austerity agenda" and the school boards that want to "claw back' gains in working conditions and professional recognition achieved over the years.

"The current negotiations potentially represent nothing less than a great divide in the history of teacher unionism and professionalism in this province," Ryan said.

He added that members should avoid making plans for students that may have to be cancelled in the fall. And, in the event of a full withdrawal of services, Ryan advised teachers to be prepared.

"Members should look to have their personal affairs to prepare for that eventuality," he said.