Premier Dalton McGuinty was on the defensive after Progressive Conservative Leader Tim Hudak penned an open letter to the Liberal leader on Sunday, expressing his concerns over the "unraveling" of the 2015 Pan American Games.

McGuinty said the Games are on schedule and will come in on budget despite Hudak's suggestion that suggest bid chairperson David Peterson and his committee are wasting time and money.

"Warning signs of problems came earlier this month, when the City of Hamilton revealed that the Velodrome venue is not on time and not on budget," Hudak wrote in the letter.

"With less than four years until the opening of the Games there has been no progress on site selection, let alone construction of venues," Hudak wrote.

McGuinty countered Hudak's characterization of the Games' progress, adding that Infrastructure Ontario has a 99 per cent success rate in completing projects on time and on budget.

"I'm very confident in our ability to deliver them on time and on budget," McGuinty said after a campaign event at the Hospital for Sick Children in Toronto.

The Ontario Liberals said there is a $45-million emergency fund already built into the $1.4-billion Pan Am budget.

With files from The Canadian Press