Education Minister Laurel Broten says she met Tuesday with Sam Hammond, the president of the Elementary Teachers' Federation of Ontario.
She says she asked Hammond to rescind the union's advice to teachers about withdrawing from extracurricular activities and keeping report card comments brief.
But Broten says they weren't able to come to an agreement.
It's the latest move by teachers' unions to withdraw voluntary activities in protest of a controversial law that freezes wages, cuts benefits and stops strikes.
Hammond wasn't available for comment, but he has said that the advice he gave ETFO's 76,000 members conforms with ministry policy, which tells teachers to use their "professional judgment" when completing progress reports.