As Liberal campaign co-chair in 2011, Wynne was involved in the politically-motivated decisions to cancel the two energy projects to save Liberals seats in the suburbs west of Toronto, said Progressive Conservative critic Rob Leone.
"With complete disregard for taxpayers, Wynne treated public funds as if they belonged to the Liberal party, and now taxpayers are left with the bill," Leone told reporters.
The Liberals pointed out Wynne's name was absent from a list of 18 names the Conservatives released last fall of people they wanted to testify at committee hearings into the gas plants.
While the Tories are demanding committee hearings into the cancelled gas plants right after the legislature resumes Feb. 19, the New Democrats want a full-blown public inquiry.
The ball is clearly in Wynne's court, said NDP Leader Andrea Horwath: agree to either committee hearings or a public inquiry into the decisions to scrap the gas plants and move the projects to southwestern and eastern Ontario.
"One way or another, the people deserve the answers and it's up to Ms Wynne to decide which way that's going to happen," Horwath told reporters.
"It's a choice that she's going to have to make."
Wynne wouldn't address the issue during an interview with The Canadian Press Wednesday, and said she wants to have talks with the opposition party leaders on a wider range of topics.
"The fact that Andrea chose to talk about the gas plant issue and a public inquiry, that's her prerogative," said Wynne.
"She can begin with whatever subject she chooses, but I'm going to be looking for a broad discussion of issues."
The Tories also released an internal memo from the Ontario Power Authority, dated Oct. 3, 2012, which they said "clearly" showed the Liberals interfered and tried to hide documents related to the cancelled gas plants.
In the memo, Leone said, a former Liberal political staffer instructed the OPA to redact and leave out information requested by the legislature.
"This is nothing less than an orchestrated cover-up on the part of the government, who was running from the truth," said Leone.
"This is evidence that the government misled the public and instructed the OPA not to search for key documents."
But the Liberals denied Leone's allegations, saying the individual mentioned in the memo was a public servant.
The government eventually released over 60,000 documents on the cancelled energy projects, but Leone said the Opposition is convinced more are being withheld.
Both opposition parties said the public is entitled to know the truth about the reasons behind the decisions to cancel the plants.
"The bottom line is the people of this province deserve answers when it comes to the behaviour of the Liberals in 2011," said Horwath.
"We are not some kind of regime where the ruling elites take money from the public and use it to keep themselves in power. That's not a democracy."
Premier Dalton McGuinty blamed the non-stop debate over the gas plants for proroguing the legislature when he resigned Oct. 15, just hours before committee hearings into the projects, and a rare contempt of Parliament motion, were to begin.
If Wynne doesn't agree to hearings, she can expect legislative business to be tied up again as the Tories try to force her hand until a committee is struck to study the situation, said Leone.
"We'll do what we have to to make that happen," he said.