05/19/2015 11:36 EDT | Updated 05/19/2016 05:59 EDT

High school teachers' talks with province to resume Wednesday with new mediator

TORONTO - Ontario high school teachers and the province return to the bargaining table this week as school boards try to end three local strikes by having them declared illegal.

This is the first round of negotiations under a new bargaining system the Liberal government introduced last year, separating the process into local and central talks.

The central talks between the Ontario Secondary School Teachers' Federation and the province have been stalled for weeks, but they will resume Wednesday with a new mediator.

More than 70,000 high school students have been kept from class for weeks as teachers in the Toronto-area regions of Peel and Durham and the Sudbury-area Rainbow District are on strike.

The three boards have asked the Ontario Labour Relations Board to declare the strikes illegal, arguing they are really over central issues such as class sizes and not matters being handled at the local tables.

That hearing is into its third day today, while the Minister of Education has also asked a separate arm of the labour board to consider whether the students' school years are in jeopardy.

Education Minister Liz Sandals has not yet said if the province is considering back-to-work legislation.

High school teachers in Ottawa and Halton Region will begin an administrative strike Thursday.

They will partially withdraw services, which means teachers won't add comments to report cards or attend staff meetings or school board meetings, and will hold some picket lines over the lunch hour. Regular school operations will continue, as will field trips and extracurricular activities.

Elementary teachers across the province are staging a similar job action, withdrawing from administrative duties but continuing with classes and extracurriculars.