TORONTO -- Ontario Premier Kathleen Wynne was complicit in the mass deletion of emails on cancelled gas plants by senior Liberals in former premier Dalton McGuinty's office, the Official Opposition charged Monday.

Wynne was a member of the Liberal cabinet when the chiefs of staff in McGuinty's office and the Ministry of Energy deleted emails on the gas plants in Oakville and Mississauga, said PC critic Rob Leone.

"Frankly she should dissolve the legislature so we can get to an election, but failing that, she's complicit in this scandal and has a responsibility to the people of Ontario to quit," Leone told reporters.

The Ontario Provincial Police launched a criminal investigation Friday into the mass destruction of gas plant documents by senior Liberals after the province's privacy watchdog found top Liberal staff broke the law by deleting their email accounts.

The Tories kept up the pressure on Wynne during Monday's question period, demanding she instruct the former staffers who deleted their email accounts, some of which were moved onto USB keys, return the information to government.

"We need you to come clean, premier," said PC energy critic Vic Fedeli. "Will you now direct your staff to fully co-operate with the OPP investigation, and will you demand that the stolen documents and USB drives be turned over to the police?"

Wynne said her government would co-operate with police, and had taken steps since she took over from McGuinty in January to make sure staff are aware of their obligations to retain government records, including emails.

"On the issue of the documents, I agree with the conclusions of the privacy commissioner, that this should not have happened, that emails should not have been deleted," Wynne told the legislature.

"We will work with the privacy commissioner to ensure that a better protocol is in place going forward and that the changes that need to be made are made."

The NDP said they too were convinced Wynne knew emails on the gas plants had been deleted when she took over as premier, and accused her of trying to hide the true cost of the cancellations, now estimated at $585 million, far above the $230 million the Liberals had been claiming.

"I don't believe that the current premier was unaware of all of this happening," said NDP Leader Andrea Horwath.

"You can't tell me she took over the reins of her party with this being the biggest issue -- in fact it led to the resignation of her predecessor -- and she had no idea about it."

Horwath was also fuming about a statement from McGuinty late Friday in response to the OPP's criminal probe, in which the former premier said "at no time did I condone or direct the deletion of emails or documents which ought to have been preserved."

"I think Ontarians want to know why (McGuinty) himself isn't taking any responsibility," said Horwath.

"It seems like on the Liberal benches it's the blame game all around, but nobody is taking responsibility for the destruction of records."

OPP Commissioner Chris Lewis said Friday that the force's Criminal Investigation Services would probe Tory complaints about "alleged impropriety" by former top staffers in McGuinty's office and the Ministry of Energy.

The Conservatives again called on the NDP to vote against the minority government's budget Tuesday and trigger an election, wondering how the party could condemn the Liberals for the gas plant fiasco but still prop them up on confidence votes.

But Horwath said the New Democrats would keep their promise to vote for the budget because it includes many of their ideas such as a 15 per cent cut in auto insurance premiums and the creation of a Financial Accountability Officer.

"We now will have a financial accountability office in place so that we can make sure that scandals like this don't happen in the future, not just with this government but with governments going foward," she said.

"That's important work and we're not going to walk away from it."