The premier said he met with Prime Minister Stephen Harper on Tuesday to talk about how they could work together on the massive mining project about 500 kilometres north of Thunder Bay.
"We need to put a road up there, we need to extend electricity transmission up there, we need to invest the skills and training levels of our First Nations communities," he said.
"This is a big project, we can't do it on our own, so what I invited the prime minister to do is to give some thought as to how we might partner together with our First Nations communities to take every advantage of this new opportunity in our backyard."
McGuinty said he believes he piqued Harper's curiosity — "if not his real interest" — in developing the Ring of Fire, which includes one of the largest chromite deposits in North America.
Chromite is a key ingredient in the production of stainless steel. However, the project also has the potential for the production of copper, nickel and platinum.
Cliffs Natural Resources plans to invest $3.3 billion to develop a chromite mine, a transportation corridor and a $1.8-billion smelter near Sudbury.
But the Ontario government is facing opposition from environmentalists and some aboriginal and northern communities.
Many First Nations complained they were not consulted about the Cliffs' development, and expressed concern about the impact of the mine on such a pristine area.
McGuinty has also come under fire for suggesting that he may give Cliffs an exemption from the Mining Act to process a large amount of the chromite offshore.
The New Democrats want as much of the ore as possible smelted and refined in Ontario, and say more processing facilities should be built to make sure the jobs stay in the province as well.
The McGuinty Liberals are still negotiating a final contract with Cliffs, and haven't said whether taxpayers or Cliffs will be paying for an access road that is estimated to cost $600 million.
The premier is also facing questions about why he kept his meeting with Harper under wraps.
It wasn't mentioned in McGuinty's daily itinerary that is sent to reporters, even though it has included meetings with visiting politicians in recent weeks.
Asked why the meeting was kept secret, McGuinty's staff said the premier has private, informal meetings with politicians from time to time.