But the governing Liberals warned Friday that a controversial new anti-strike law gives them the power to intervene.
The Ontario Secondary School Teachers' Federation is instructing its members who are in a legal strike position to stop those tasks — and others — starting Nov. 7, including support staff.
Among the sanctions, teachers are being told not to attend staff or department meetings, communicate with parents outside of the regular school day or participate in activities involved in standardized tests.
Local bargaining units may also decide to instruct teachers to stop doing other tasks, such as not submitting student attendance or participate in curriculum or course writing.
The memo posted Friday on the union's website instructs teachers, occasional teachers, education assistants and others to continue to provide instruction to students, do course preparation and marking. They may also provide extra help to students.
The strike actions are designed not to "negatively impact" students, said OSSTF president Ken Coran. They're meant to spark serious discussions about getting a collective agreement with local school boards, who are the employers.
"It means really you focus on the students in the classroom. That's the intent," he said in an interview.
"Let teachers teach, let support staff do support staff work, as opposed to some of these other things that are obviously part of the job because they're defined in collective agreements or they're defined in the Education Act. But they're not really the meat and potatoes of what happens in a classroom with student learning."
Education Minister Laurel Broten said she's very concerned that the union wants to take strike action, but the government can intervene.
The minority Liberals could impose an agreement — which would effectively end a strike, she said.
"In addition, the government could intervene to end strike actions outside of imposing an agreement," she said in a statement.
Coran acknowledged that the minister "could stop anything if she chooses to do so."
He said teachers and other education workers in five to 10 school boards scattered across the province are in a legal strike position, but that number will rise after Nov. 7.
OSSTF, which represents about 60,000 members, is among three unions who are fuming over the new law brought in by the cash-strapped Liberals, which also cuts benefits and freezes the wages of senior teachers.
Some teachers who aren't necessarily in a strike position have already withdrawn from voluntary activities such as coaching and parent-teacher meetings in protest of the controversial law.
The Elementary Teachers' Federation of Ontario has advised its 76,000 members to write only the bare minimum on report cards.
Broten met with ETFO president Sam Hammond earlier this week to see if he would rescind the advice, but he wouldn't back down.
The legislation, which imposed a new two-year contracts on thousands of teachers, is based on an agreement the province reached with English Catholic and francophone teachers. It included three unpaid days off in the second year and cuts sick days in half to 10 a year.
But ETFO, OSSTF and CUPE Ontario, which represents 55,000 workers such as custodians and school secretaries, refused to sign on.
When the bill passed with the help of the Progressive Conservatives, the three unions vowed to fight it all the way to the Supreme Court of Canada.
Rattled by the unions' declaration of war, the Liberals are trying to mend fences with the labour groups whose financial and organizational support helped get them re-elected over the past nine years.
Premier Dalton McGuinty bought time for the Liberals to repair that relationship when he prorogued the legislature last week and announced he would step down once a new leader is chosen.
McGuinty said he shut down the legislature to allow for a "cooling off period" that would give them time to negotiate with unions and the opposition parties on a wage freeze for nearly 500,000 public sector workers.
But it has only infuriated the unions, who called it a "flimsy excuse" to deflect attention from other scandals the government was facing.
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