TORONTO -- Ontario's auditor general will examine millions of dollars in government payouts to teachers' unions to cover negotiating costs.

The Liberals supported a Progressive Conservative motion at committee that requested Auditor General Bonnie Lysyk review the payments and report on where the money came from and what it was intended to fund.

"I'm quite confident that there is not a problem, but...we'll certainly work with her to get the information she needs to do that review," said Education Minister Liz Sandals.

The Liberal government paid $3.74 million to various teacher and support staff unions in the 2008, 2012 and the current rounds of contract talks as the government transitioned to a new bargaining system.

Sandals originally said the payouts were made without receipts from the unions to show their costs, but Premier Kathleen Wynne later said the government would ask for receipts.

Even though the unions were not asked for invoices or receipts for the payments dating back seven years, Sandals said documentation does exist.

"I've said very clearly that there are accountability processes and verification processes and schedules of allowable expenses," she said.

But Sandals said she couldn't guarantee she would be able to hand over everything the auditor general seeks.

"The documentation we will certainly share, but I'm not making some blanket assumption that I can fulfil every wish of the auditor general when I don't know what it is she wishes," she said.

Progressive Conservative Lisa MacLeod, who introduced the motion, says "it doesn't look good" that such large sums of money were promised to the unions undocumented.

"When you look at undocumented payouts to unions who run attack ads against the main Opposition party in the legislature, you have to wonder if that's an appropriate use of government funds," MacLeod said, referring to donations by some of the unions to a coalition that ran anti-Tory ads during the last election.

"I think it's a misappropriation."

The Liberals paid $2.5 million this year to the Ontario Secondary School Teachers' Federation, the Ontario English Catholic Teachers' Association and the French teachers' union. In 2008 and 2012 a total of $1.24 million was paid to OSSTF, the Canadian Union of Public Employees, which represents support workers, and the French teachers' union.

Lysyk is expected to present her report by the spring of 2016.