TORONTO - Ontario's public high school teacher's union was circling the wagons around Premier Dalton McGuinty's flagging Liberal government at a weekend conference.

Union leaders warned on Saturday of a return to the bitter labour disputes and budget cuts of the Progressive Conservative government under former Premier Mike Harris if the Tories unseat the governing Liberals in October's provincial election.

"Publicly funded education will be under direct attack" should Tory Leader Tim Hudak become premier, Paul Elliott, vice-president of the Ontario Secondary School Teachers' Federation, told the group's annual meeting in Toronto.

The union must mobilize in support of candidates who will "protect and enhance" the education system, rather than undermine it, Elliott, the union's vice-president, told some 800 teachers and support staff.

Recent polls suggest most voters are primed for a change of government after eight years under Dalton McGuinty, who calls himself the "education premier."

Education Minister Leona Dombrowsky was only too happy to add her voice to union leaders' message, telling teachers they're better off sticking with what they've got.

Though she wouldn't give any hints of the Liberals' electoral platform, the minister said the government has made education a priority and brought two terms of "unprecedented labour peace."

She said the Conservatives haven't changed since Harris was leader and would "create another crisis in education" if elected.

"We've seen that and we don't want it again," she said to thunderous applause.

Union president Ken Coran was quick to say after the speeches that it wouldn't be fair to pick sides until each party reveals its platform. But he said voters should "learn from past mistakes."

Another Harris-style government "would have the same devastating effects" today as it did back then, he said.

Harris held back-to-back majorities between 1995 and 2002.

Ontario's deficit-fighting Tories cut $400 million from the budgets of the province's secondary and elementary schools in 1996 and years of strife between Harris and teachers followed.

Students in Ontario were kept out of their classrooms on several occasions during a turbulent period in education during Harris's time as premier.

Strikes, including one illegal two-week walkout, were held to protest cuts to education budgets, low wage increases and longer working hours for teachers.