TORONTO - Ontario's Progressive Conservatives say the Liberals' decision to bail out the MaRS real estate project in Toronto could cost taxpayers even more than the $1.1-billion gas plants scandal.

The Tories say documents they obtained from a government whistleblower show the $317 million to buy the Phase 2 tower of the MaRS innovation research complex in downtown Toronto is far from the total bill.

PC finance critic Vic Fedeli says there are side deals that would see the government pay $106 million to fit up the space for tenants and cover $45.7 million in operating shortfalls between now and 2018.

Fedeli says the most concerning item is amortization of $11 million a year over 40 years, and he wants Premier Kathleen Wynne to explain if that means taxpayers are on the hook for another $440 million.

Wynne said Thursday the deal to bail out the real estate developer and MaRS was not made public because it hasn't been finalized, and insisted it would be good for the government to own more office space across the street from the legislature.

But Fedeli says the Liberals kept the liability out of the May 1 budget and never talked about the MaRS bailout because they didn't want to be embarrassed during the election campaign by the bad deals they negotiated.