TORONTO -- The Elementary Teachers Federation broke the law when it advised members to withdraw from extracurricular activities, the Ontario Labour Relations Board ruled Thursday -- weeks after the union lifted its ban on after class clubs and sports.

Most of the province's public elementary and secondary school teachers stopped supervising extracurricular activities last fall to protest legislation that imposed contracts with a two year wage freeze on 126,000 educators.

Education Minister Liz Sandals, keen to repair relations with teachers, said only that the government would review the board's ruling.

"While we will review this decision, our focus remains on our ongoing discussions with ETFO and re-building relationships across the sector to ensure we continue to build on one of the best education systems in the world," Sandals said in a statement.

The Progressive Conservatives said the ruling vindicates their position that the union had no right to tell teachers not to supervise extracurricular activities.

"We don't think that the government should be able to tell you what to do with your voluntary time, but a union shouldn't be able to tell you what not to do with your voluntary time, and I think that came loud and clear from the labour relations board," said PC education critic Lisa MacLeod.

The Tories also lashed out at Premier Kathleen Wynne for re-opening the ETFO contract to reach a new deal with the union, and said they don't believe the Liberals' claims that there was no new money offered to the teachers.

"I think parents and taxpayers will be very disappointed to know that Kathleen Wynne is re-opening a legislated agreement for this union," added MacLeod.

The Trillium Lakelands and Upper Canada District school boards challenged the Elementary Teachers' Federation's decision to advise its members to stop participating in after class activities.

The board ruled ETFO engaged in illegal strike action under Ontario's Education Act, but the ruling only applies to the union's actions within those two boards.

ETFO had appealed to have the matter dropped because the province later repealed Bill 115 -- after it was used to impose contracts on teachers Jan. 1.

But the board said even though the bill was repealed, the collective agreements imposed by the legislation continued to exist and be in force.

"The withdrawal ... in voluntary co-instructional (or extracurricular) activities ... constitutes a 'strike' within the meaning of the Education Act," the board said in its ruling.

The union said it will abide by the ruling, adding the decision confirms its assertion that the advice to members about withdrawing voluntary services was not a directive.

"This ruling reinforces the position of ETFO that individual members have the right to make personal decisions about whether or not to participate in voluntary or extracurricular activities," said union president Sam Hammond.

"It also makes clear that school boards cannot compel their employees to perform voluntary services or discipline them for not doing so."

The labour relations board said no final orders were being issued because the ETFO has made a charter challenge to the definition of strike in the Education Act, and that matter remains outstanding.

It also criticized the behaviour of both the government and the union.

"Frequently throughout these proceedings both parties accused the other of grandstanding ... then immediately proceeded to do the same themselves," wrote board chairman Bernard Fishbein.