TORONTO - The Opposition Conservatives claimed Thursday that the governing Liberals are violating Ontario's Election Act by having a third party buy television commercials to promote their re-election bid.

The pro-Liberal, anti-Tory TV spots were paid for by the so-called Working Families Coalition and are already being broadcast across the province and online.

The coalition, made up of various unions, including the Canadian Auto Workers, was responsible for the "Not this time, Ernie'' campaign that helped defeat the Conservatives under Ernie Eves in 2003.

Conservative party president Blair McCreadie said the coalition is little more than a front for the Liberals, and is run by people like Don Guy, Premier Dalton McGuinty's former chief of staff.

"I think there's certainly evidence that the Working Families Coalition is in fact acting as an agent of the Liberal Party,'' McCreadie said.

"I think voters should be upset, because it's important to ensure that we have an open, fair and transparent election.''

However, Liberal spokesman Ben Chin dismissed the Opposition's allegations as "completely false.''

Chin said the Conservatives are "throwing muck'' in a desperate attempt to deflect attention away from their controversial proposal to fund faith-based schools, which the Liberals warn would take money out of Ontario's public education system.

"What's interesting is that there is a coalition of hard-working Ontarians who don't want to see the Conservatives elected,'' Chin said. "You can ask them why.''

The coalition did not return e-mails Thursday requesting comment on the Conservatives' allegations.

McCreadie has written to Ontario's chief electoral officer asking for an investigation into what the Conservatives claim are links between the Liberals and the coalition.

He said the group's expenditures and contributions should be listed under the Liberals to prevent the party from getting around Ontario's rules on campaign spending limits.

"Truly independent third-party groups have a right to participate in this process,'' McCreadie said.

"However, if that third party is not truly independent and is being used as an agent to circumvent the contribution and expenditure limits under the Elections Finances Act, then we certainly have a problem with that.''

An Elections Ontario spokesman said the office does not confirm or deny when it has received a complaint, but when it does, it reviews the material and acts accordingly.

The Conservatives want the investigation to be completed before the Oct. 10 election.

Ontario's campaign spending limits allow parties to spend 96 cents for each voter, or between $5 million and $6 million.

McCreadie said he had heard the Working Families Coalition planned to spend more than $4 million on advertising for the election, which he believes allows the Liberals to circumvent the rules.