Ontario Premier Kathleen Wynne is looking at changing the laws surrounding election spending after an annual Elections Ontario report revealed that third-party spending tripled in the last provincial election.

The CBC's Mike Crawley reported Monday that union-backed groups spent more than $6 million in advertising in the 2011 Ontario election — three times what was spent in 2007, and more than the NDP's total campaign budget.

Sam Hammond, the president of the Elementary Teachers' Federation of Ontario (ETFO), defended the spending spree, calling it "effective."

'It's very important for us to get our message out'—Sam Hammond, Elementary Teachers' Federation of Ontario president

"It's very important for us to get our message out," he said.

In the Elections Ontario report, Ontario's Chief Electoral Officer Greg Essensa has urged the provincial government to adopt spending limits for unions and other special-interest groups. It's one of several recommendations that are being made to reform the elections laws.

Essensa notes that only one third party raised and spent more than $1 million on political ads in 2007. But in 2011, three third-party groups exceeded this threshold, with the ETFO representing the largest single spender at nearly $2.7 million.

The Ontario English Catholic Teachers Association spent $1.9 million, while the Working Families Coalition, funded by a variety of unions, spent just over $1 million.

Wynne said she would look at the recommendations but didn't make clear when a decision may come.

"I'm very interested in looking at them and open to changes that could be made," said Wynne.

Lisa MacLeod, Progressive Conservative MPP for Nepean-Carleton, said "there needs to be regulations and rules in place that make it more fair, more consistent."

Currently, Quebec, British Columbia, Alberta and New Brunswick have controls on third-party advertising spending. There are also limits at the federal level.

Crawley said it wasn't clear whether the changes to the laws could come before the next election.

With files from the CBC's Mike Crawley