TORONTO -- Ontario's beleaguered premier is promising to try to stop thousands of public elementary teachers from staging an "illegal strike" Friday by walking out of class to protest their controversial new contracts.

The teachers are no longer in a legal strike position now that the cash-strapped province has imposed new two-year agreements that cut benefits and freeze the wages of most educators, Premier Dalton McGuinty said during a hastily-called news conference late Wednesday.

"Teachers do not want to do anything that's illegal," he said.

His government will seek a cease-and-desist order from the Ontario Labour Relations Board in an effort to avert a strike that would close primary schools across the province, he said.

But McGuinty wouldn't say whether he'd go after teachers who still walk off the job Friday. Instead, he urged them not to engage in what he called an "illegal strike."

"If you feel your dissatisfaction has not been heard, I assure you it has," he said.

"But let's agree to have this matter settled in court and not in our schools. Let's leave our students out of it."

The Elementary Teachers' Federation of Ontario insists it's not a strike, but a one-day political protest that's protected under the Charter of Rights and Freedoms.

"This has nothing to do with revenge or anger," said ETFO president Sam Hammond. "This has to do with principled positions in terms of democracy in this province and in this country."

The Liberals argue that it is an illegal strike under Bill 115, the controversial anti-strike law that gave them the power to impose the contracts on teachers.

Under Ontario's labour laws, engaging in illegal strike activity can carry a penalty of up to $2,000 per person and $20,000 for a trade union.

The union had offered a truce to the Liberals, promising to hold off on any action if they didn't use the law to force new contracts on them before a new premier is chosen Jan. 26.

Instead, Broten imposed collective agreements Jan. 3 on 126,000 public school teachers and education workers, which cut their benefits and froze most of their wages to battle the province's $14.4-billion deficit.

She promised to repeal the law -- which four unions are challenging in court -- by the end of the month. But Hammond said it's an empty gesture when she's already used it to trample on teachers' rights.

"I would say to anyone who says let this go, let bygones be bygones: That's not going to happen," he said.

The one-day protest is what his 76,000 members want, Hammond said. And the union can't fine any of its members if they don't participate, because it's a protest, not a strike.

There are no plans for further protests, but the union leader said he's not ruling anything out.

"Quite frankly, with this minister, there is nothing to talk about," Hammond said. "She took a very provocative and disgraceful step in terms of implementing terms and conditions on Jan. 3. And frankly, there's nothing left to talk about."

However, Hammond said he would sit down and talk with a new premier.

The contracts were also imposed on public high school teachers, who are expected to maintain their boycott of extracurricular activities.

Top brass at the Ontario Secondary School Teachers' Federation were to meet Wednesday, but president Ken Coran was not available for comment.

However, the union posted a message on its website Monday saying while teachers wouldn't strike, "voluntary or extracurricular activities will not resume."

It's the latest twist in the labour drama that's engulfed the Liberals, who have alienated a powerful group that's helped them stay in power for nine years.

But the showdown has helped them reach agreements with other public sector workers.

The Ontario Public Service Employees Union, which represents 38,000 public servants, announced Wednesday that it had struck a two-year tentative agreement with the province.

The government said it includes a commitment to implement a two-year wage freeze, but details won't be released until the agreement is ratified. Those votes are scheduled for Jan. 21-23.

It's not a perfect agreement and OPSEU members may not like it, said union president Warren "Smokey" Thomas. But it was the best deal they could make when the government seemed "very willing" to legislate contracts.

"In our opinion, it's better to bargain something than have it imposed," Thomas said. "Frankly, if it had been imposed, both sides usually end up being pretty unhappy."