Ontario's governing Liberals are proposing to enshrine a system that's been used in the past to negotiate new labour agreements with teachers and other education workers.

Education Minister Liz Sandals says she'll introduce legislation today that, if passed, would take effect early next year before most of the existing agreements expire.

The bill would ensure trustees associations are represented at the main bargaining table, along with the government and unions, including those for support staff.

It would also require that all three parties ratify any central agreement.

The Liberals sparked a labour war with public school teachers last year when they forced new contracts on them and prevented them from striking in an effort to freeze some of their wages.

Taking a hard line resulted in major protests, including rotating one-day strikes by elementary teachers — which the Liberals said they wouldn't oppose — and the withdrawal of extracurricular activities by high school teachers.

It also alienated a powerful group that's helped the Liberals get re-elected over the last decade.

When Premier Kathleen Wynne took office, she promised to change the system to avoid such confrontations as her cash-strapped government fights a $11.7-billion deficit.

Over the last few years, new contracts with teachers have been reached through a so-called provincial roundtable, where representatives for the government, school boards and unions hammer out a framework agreement.

That template is then used in local negotiations to fine-tune a final agreement, as the school boards are technically the teachers' employers.

But the only legal negotiations under the current law are those between the local boards and the unions, said government officials.