TORONTO -- Public high school teachers at nine Ontario school boards held a one-day strike Wednesday -- the second in as many weeks -- as the province's education minister urged them to return to the bargaining table.

The teachers have been without a contract since their last one expired at the end of August, and their union has blamed the Progressive Conservative government for the lack of progress in their negotiations.

Education Minister Stephen Lecce said the government has reached out to the Ontario Secondary School Teachers' Federation through a mediator to offer new bargaining dates in an effort to reach a deal.

"My message to OSSTF is to cancel the strike that is needlessly hurting students in the classrooms of this province," he said.

Union president Harvey Bischof said his team was willing to return to the table at any time and has also provided bargaining dates of their own to the mediator.

"What they should do is bring proposals to the table," he said.

The two parties haven't held talks since last week, when the OSSTF launched a one-day strike that affected all high schools -- and some elementary schools -- in the province.

All public high schools in Toronto and eight other school boards in southwestern, eastern and northern Ontario were closed Wednesday as a result of the latest job action.

The province has signed new deals with two unions representing education workers, but remains at odds with a number of major teachers' unions, which are pushing back against the Tory government's plans to increase class sizes and introduce mandatory e-learning courses.

The government has said the key issue at the bargaining table is compensation, with the province offering a one per cent annual wage increase, and the union asking for around two per cent.

Bischof said the union has not ruled out taking further job actions -- including a full strike.

"Those things are certainly a possibility," he said. "It's one that I hope we never have to get to."

NDP Leader Andrea Horwath blamed Premier Doug Ford for what she called a "crisis in education."

"This government has been laser-focused on one thing ... and that is making classroom cuts and blaming anybody but themselves for the fallout," she said. "Teachers, students, and parents have all been clear -- cancel the cuts."

Interim Liberal Leader John Fraser said the fact the government and union can't even seem to agree on bargaining dates is a bad sign.

"The government needs a more effective approach to negotiations," he said. "They obviously don't have a plan."

Meanwhile, a few dozen teachers -- bundled in heavy coats and scarves -- picketed in sub-zero temperatures outside an alternative high school in Toronto on Wednesday morning. Passing cars honked their horns in support.

Nabeel Salloum said he's seen a monumental shift in the classroom over the past year, with two colleagues being laid off at his small school, where only six teachers remain.

"We could only provide so many courses," he said. "We're trying to stay with the mandatory courses as much as possible, but the elective courses have been decimated because there's just not enough teaching staff to expand the program."

He said they had to cancel classes including media arts, drama and fine arts.

Cristina Dias, who is in her fifth year of teaching, said the tone of the bargaining session has been disheartening.

"It's really scary," she said. "You work really hard to get to where we are. Entering into a career where all this job action is happening is really intimidating. I'm still in this profession because I love my job, and I don't want to give up on it."

Cassandra Kirchmeir Gitt, who has been a teacher for 29 years, said many of her students and their parents are supportive of the job action, but it still takes a toll.

"You go between hope -- because we have to have hope -- and a little bit of worry, despair," she said. "But you have to have hope that people will see it is 100 per cent worth it -- oh, maybe 110."

This report by The Canadian Press was first published Dec. 11, 2019.