TORONTO -- A fight between Ontario's Liberal government and the opposition parties over two cancelled power plants escalated Friday when Premier Dalton McGuinty said he does not want documents on the projects released until negotiations with the developers are concluded.

The government will eventually release all documents on the cancelled gas-fired generating stations in Mississauga and Oakville, McGuinty said after warning that a premature release could end up costing taxpayers even more money.

"There are two public interests we have to protect: one is the public interest that demands that we release the documents. The other is the public's interest that demands that we do that at a time that does not compromise taxpayers' interests," he said.

"For me the issue is not whether we release this information. It's when do we release it."

Speaker Dave Levac ruled Thursday that Energy Minister Chris Bentley violated members' privileges by refusing to turn over all the documents on the cancelled electricity projects to a legislative committee.

The Speaker gave the three parties until Sept. 24 to work out a way to settle the dispute, but the Progressive Conservatives say there is only one resolution: release all the documents immediately.

"The solution is simple: hit print, and table the documents now," said Tory house leader Jim Wilson.

"Waiting just gives the Liberals more time to squirm, and room to bury the facts. Give us the documents so we can get on with holding this government to account, which is our job."

McGuinty wrote PC Leader Tim Hudak and NDP Leader Andrea Horwath Friday saying it would be "irresponsible" for them to make taxpayers pay a higher price because of what he called the premature release of the information.

"I would like to express my disappointment over the insistence of Ontario's opposition parties to play politics with this sensible issue," wrote McGuinty.

Horwath quickly fired back with her own letter accusing McGuinty and Bentley of using "a variety of stall tactics to keep the costs of these private power deals from the public," and demanding the documents be released immediately.

"The people of Ontario have a right to know how their money has been spent, and they have a right to know this in a timely manner, not at an indefinite point in the future," wrote Horwath.

The Liberals have admitted taxpayers are on the hook for $190 million for halting construction of the Mississauga generating station just days before last fall's election, but so far have refused to say what the potential costs could be for cancelling the other power plant in nearby Oakville.

The premier is trying to protect the Liberal party, which made the decisions to cancel the generating stations to save Liberal seats in the area west of Toronto, charged Wilson.

"What they don't want us to see is they're not being truthful about the penalty clauses in these contracts," he said.

"The $190 million is the tip of the iceberg and we don't know the cost of Oakville -- I bet it's in the hundreds and hundreds of millions of dollars -- and he doesn't want people to know that."

The opposition parties say it's highly unlikely the house leaders will come up with any kind of compromise on the gas plant documents, especially as they haven't even been able to agree on re-establishing committees for the current session of the legislature.

If the documents aren't made public by the end of day Sept. 24, Wilson said the Tories will table a a motion declaring Bentley in contempt of Parliament, which would cancel all other business at the legislature, including question period, until the matter is dealt with.

The Tories and NDP combined have one more vote than the minority Liberal government, which could result in a very rare finding of contempt by the Ontario legislature.