Progressive Conservative Leader Tim Hudak was the only leader with a public appearance, showing up with his family to chat with volunteers at a Toronto campaign office.
Hudak left the day's campaign attacks to Tory MPP Vic Fedeli, who once more slammed the Liberal government's bailout of a Toronto real estate project.
The deal was brought to light when the Tories released documents on Thursday showing the province gave $71 million to buy land to expand the MaRS innovation and research complex, and a $234-million loan for a new tower.
The Tories have said documents show the money couldn't be repaid and the Liberals had agreed to buy the new building to prevent MaRS and the developer defaulting on the loan.
According to the documents, the development's $317-million purchase price would include the $234-million government loan.
But Fedeli said taxpayers could be on the hook for three times more once all costs for building are factored in.
"Kathleen Wynne has just used your tax dollars to purchase the Trump Tower of Canadian bureaucracy," Fedeli said.
"The money that was blown on Kathleen Wynne's secret real estate deal could've gone to hire nurses or teachers for special ed kids."
Fedeli urged Wynne on Sunday to release all documents related to the bailout, saying she must "come clean" about the deal and its final price.
Wynne has said the deal was not made public because it hasn't been finalized.
She has also said the fact the province now has to buy the MaRS office tower to stop the charity from defaulting on loans will give the government more office space across the street from the legislature.
The Liberals, meanwhile, sent out Economic Development Minister Eric Hoskins to accuse Hudak of adopting policy ideas from "right wing extremist radical elements" in the U.S. after meeting with certain conservative thinkers in Washington, D.C.
Those meetings preceded Hudak's controversial campaign pledge to cut 100,000 public sector jobs in Ontario if elected, Hoskins said.
"It's what he did with the information that he received from these right-wing elements that shaped a far-right, extremist, reckless set of policies and proposals," Hoskins said.
The Tories, however, said the Liberals were regurgitating old news and added that Hudak has been open about how he develops his ideas.
Hoskins' attack on Hudak's policy influences coincided with the release of a new Liberal ad that criticized the Tories for disputed job numbers in their election platform. The figures have been challenged by some economists who've said they're inflated due to an alleged misinterpretation of data.
The Liberal ad suggests Hudak is demonstrating questionable leadership by not admitting to "the mistake."
The NDP also released a new ad on Sunday which features clips of people saying why they're going to vote for party leader Andrea Horwath.
Those in the ad say they're tired of Liberal "corruption" and don't want a Tory government that will make deep cuts to the public sector either.
"Andrea Horwath is the most trusted leader in Ontario right now," says one person in the ad. "She's a very honest individual and I think that's what we need," says another.
The election campaign is set to ramp up next week with all three party leaders facing off in Tuesday's televised debate.
Election day is June 12.
— with files from Paola Loriggio and Will Campbell.