The Ontario government says it saved $40 million when high school teachers with three boards went on strike for several weeks last year.

In response to questions on Monday from the NDP, Education Minister Liz Sandals said part of the reason for lower-than-expected spending was that teachers who go on strike don't get paid.

NDP Leader Andrea Horwath had pointed to a line in the budget that showed education spending was $430 million less than projected in the fall economic statement, saying the Liberal government is cutting education spending.

Sandals said Monday after question period that amount was due to the amortization of capital costs, slightly lower-than-projected enrolment and the strike savings.

But her office wasn't able to say until four days later how much of the $430 million was attributable to not paying striking teachers.

More than 70,000 high school students in the Toronto-area regions of Durham and Peel and the Sudbury-area Rainbow District were out of class for weeks as their teachers went on strikes that were ultimately ended when the Ontario Labour Relations Board ruled them illegal.