TORONTO - Ontario's governing Liberals are looking into rules that allow retired teachers to pad their pensions with supply-teaching work, but the government won't clamp down on the practice, Education Minister Leona Dombrowsky said Monday.

"We don't tell boards who to choose," she said. "What we do say is that we expect that they look for the best person in a particular situation or circumstance."

Dombrowsky was reacting to a report that Ontario's cash-strapped school boards squandered $16.7 million in the last academic year by giving retirees supply work rather than hiring new teachers.

The minister said she's talking with the Ontario Teachers Federation about the current rules, which allow teachers to work up to 95 days in first three working years after retirement without it affecting their pensions, and up to 20 days every year thereafter.

Before 1990, they could only work up to 20 days before their pensions were affected, but the rules were changed to address a teacher shortage.

Dombrowsky wouldn't commit to reverting back to the old rules, even though there's no longer a shortage.

Her priority is to have the most qualified teacher at the front of the classroom, not necessarily the person who comes at the lowest cost, she said.

While she still has faith in school boards and administrators to make those decisions, new teachers need experience and the boards must "strike a balance" in deciding who's the best person for the job, she added.

NDP Leader Andrea Horwath said the rules should be reviewed, given the amount of money school boards are spending on retired teachers.

"I think there needs to be a balance between the value that experienced teachers bring, as well as the need to make sure that newer teachers get some experience as well," she said.

"I think there's a lot of work that needs to be done here, and it's long past due."

According to the Globe and Mail, retired teachers working in 10 school boards representing half the student population collected $108.3 million in the 2008-09 school year on top of their government-subsidized pensions.

Boards were favouring retirees over new teachers for supply assignments at a higher pay scale that, in some cases, doubled the cost to the taxpayer, the newspaper reported.

Calls to the Ontario Teachers Federation for comment were not immediately returned.

Other provinces, such as Prince Edward Island, have stopped pension payments when a teacher takes a long-term supply assignment.

Young teachers are itching to gain some experience in the classroom and Dombrowsky owes it to them to find a "better way" to make that happen, said Opposition Leader Tim Hudak.

But the Conservative leader, whose father is a retired school principal, stopped short of calling for a clampdown on the hiring of retired teachers.

Dombrowsky should simply "reach out" to the school boards and principals, he said.

"I just feel that more needs to be done to give those young teachers who just got out of school a chance to put their skills to work, get that experience and then get in that classroom," Hudak said.