Ontario Premier Dalton McGuinty. (Michael Peake/QMI Agency)

The Liberal government will release documents about gas plant cancellations when it won't cost Ontario more money, Premier Dalton McGuinty said Monday.

"The issue for us is not whether we release this documentation but when," McGuinty said, adding Auditor General Jim McCarter has already warned putting the papers out could drive up the cost to taxpayers.

The Liberals have scrapped two planned plants for Oakville and Mississauga after vocal opposition from residents.

The Mississauga plant is being moved to Sarnia for $190 million in penalties and payments to the builder.

The cost of cancelling the Oakville plant is still the subject of negotiations between Ontario and the company that was awarded the contract to build it.

Speaker Dave Levac ruled last week the opposition has a right to see the documents and gave a Sept. 24 deadline for the government to arrange their release with the Progressive Conservative and New Democrat house leaders.

McGuinty said he's asking the two opposition parties to wait until a deal on Oakville is announced.

NDP MPP Jonah Schein said Levac's ruling means the information should come out now.

"That's the way a lot of people feel — that the premier is thumbing his nose at folks here, " Schein said.

"The speaker was quite clear...we'd like to see the documents right now."