TORONTO - Several school boards across Ontario will have to justify their high trustee expenses in the wake of a spending scandal at Toronto's Catholic school board and fresh allegations of questionable charges at another board, Education Minister Kathleen Wynne said Monday.

"We sent a letter out to boards across the province that had high trustee expenses and we've asked all of those boards to explain those expenses,'' Wynne said.

The seven boards are being asked to reply "immediately'' to the letter, which was sent in May after a government report slammed spending abuses among trustees at the Toronto Catholic District School Board.

Boards with spending that "appeared to be higher than others'' include Peel District, York Region, Toronto, Sudbury Catholic, York Catholic, Halton District and London District, said spokesman Jeff Rohrer.

The boards have until Aug. 31 to respond to the request, Rohrer said in an e-mail.

Some boards are including items under the trustee expense budget that others are not, such as fees for trustee associations and board meetings, but the ministry will work with the boards to standardize the process, he said.

A second letter, which went out to all Ontario school boards, asked that they report their trustee expense policies on their board's website, Rohrer said.

Three boards -- Conseil Scolaire District Catholique de Grandes Rivieres, Simcoe Muskoka Catholic District School Board and the Conseil Scolaire District du Centre-Est de L'Ontario -- haven't complied, he added.

Wynne downplayed concerns of possible spending abuses elsewhere in the province, saying she expects that the "vast majority'' of trustees are acting responsibly.

However, recent reports that some Toronto District School Board trustees expensed items like hair salon charges, parking tickets and home cable bills are "not a good thing,'' she said.

"It's something that has to be explained and has to be caught,'' Wynne said. "And that's why you need checks and balances in place. That's what we're looking for.''

Last week, the province effectively took control of Toronto's Catholic school board after investigators found that trustees hadn't stopped using their expenses inappropriately and the board failed to balance its books as required by provincial law.

The fiasco serves as a "cautionary tale'' for all school boards, a signal that the province won't tolerate such abuse of public funds, Wynne said.

Other school boards should learn a lesson from the experience, Premier Dalton McGuinty said Monday.

"There are rules in place,'' he said after the groundbreaking ceremony of a new research facility in Waterloo, Ont.

"We should abide by those rules. It's an opportunity for all our trustees just to double-check the rules and make sure they are abiding by them.''

But opposition critics say the Liberal government has a long way to go before it can earn back the public's trust.

"They've been asleep at the switch,'' said Progressive Conservative critic Joyce Savoline, who raised the issue in the legislature Monday.

"They had the opportunity to do something about this two years ago when the Catholic board showed inconsistencies in the expenses of their trustees. Whatever little slap on the wrist that came from that experience certainly was not monitored by her staff.''

The Liberals also haven't come through on their promise to create a legislative committee that would oversee government spending on education, said NDP critic Rosario Marchese.

"As much as we should have oversight about what boards might be doing, we need oversight over the government,'' he said.

Ontario's ombudsman, who now has the power to investigate the Toronto Catholic board, has received six complaints since the province appointed Norbert Hartmann to take over control of the financial management and administration of the board.

Last month, the former bureaucrat's report found the Catholic school board spent $1.2 million on trustee expenses -- the highest cost per trustee in the province.