10/08/2014 05:10 EDT | Updated 12/08/2014 05:59 EST

How much could the MaRS building cost Ontario taxpayers?

Ontario's opposition parties say they want to know how much it could cost taxpayers to have the government bail out a real estate project in downtown Toronto.

The province gave a $224 million loan to help get a second tower built at the MaRS medical research centre and then paid $65 million to buy out an American real estate company involved in the project.

Infrastructure Minister Brad Duguid spent the past two days being grilled at committee about MaRS, which he insists is a good deal for taxpayers, noting the office tower is worth more than the money already invested.

Duguid says the government loaned the MaRS developer the money because it wanted to further develop the bio-science research cluster it helped create with the first tower, and is also paying the monthly interest on the loan until an agreement on the future of the second tower is finalized.

Progressive Conservative critic Randy Hillier was frustrated when Duguid refused to say how much the province could end up spending on the second MaRS tower, which may end up housing civil servants - not scientific researchers.

Hillier says the minister should tell the committee what the upper limit of the cost to taxpayers could be for the office tower, which remains mostly empty.

New Democrat Percy Hatfield says he doesn't understand why Duguid won't say what the upper limit is for government expenditures on MaRS when the Liberals keep claiming to be open and transparent.