Retired autoworkers fearful for their pension pestered federal Finance Minister Jim Flaherty in Oshawa, Ont. as he tried to make an infrastructure announcement.

Some held signs on Wednesday saying, "Save Our Pensions."

Flaherty, MP for Whitby-Oshawa, would only say it's a "very serious" time for the Big Three automakers, two of whom are facing possible bankruptcy protection.

He said all players -- Ottawa, Queen's Park, car makers and unions -- must make sacrifices and compromises to save the sector.

However, Premier Dalton McGuinty also warned that the province can't guarantee the pensions of all auto workers should GM and Chrysler go bankrupt.

"The money available in that (fund) is very, very modest," he told reporters at Queen's Park.

The Pension Benefits Guarantee Fund has about $100 million available. That fund has provided pensioners with up to $1,000 per month in case a private pension plan fails. The pension liabilities of the auto makers run into the billions.

"That comes nowhere near meeting any liabilities for example, for the auto sector alone, let alone all the other sectors," McGuinty said.

However, in the 1990s, GM signed up for a pension insurance fund offered by the Ontario government, CTV Toronto's Paul Bliss reports.

Finance Minister Dwight Duncan said the best way to avoid a pension disaster is to keep GM in business. "We'll just have to work to keep these companies viable," he told reporters.

Robert Runciman, leader of the opposition Progressive Conservatives, had some concerns about bailing out pension plans at the expense of taxpayers who are facing dwindling pensions themselves.

"There may be some way the government and taxpayers can assist, but to come in with a 100 per cent bailout of pension plans that most taxpayers will not have access to, I think, would be troublesome to the vast majority of people in this province," Runciman said.

Bliss said the opposition said both GM and the government should have been topping up their pensions in the good times.

Federal Industry Minister Tony Clement said any pension troubles in Ontario would be out of his jurisdiction if GM goes bust, Bliss said.

Foundation for the future

McGuinty said the possible bankruptcy of GM and Chrysler doesn't spell disaster for Ontario, noting the auto market will recover when the recession ends.

"We don't have an endless supply of money that we're prepared to put forward in this regard, but we still maintain -- on the basis of the very best advice we have received -- that there is a foundation ... on which we can build a strong future for the auto sector," he told reporters at Queen's Park on Wednesday.

"It's not happening right now," but McGuinty said in the not-too-distant future, North American auto demand could return to between 12 million and 17 million new vehicles per year.

With the collapse in demand brought about by the recession, about 10 million vehicles are currently being purchased on an annualized basis.

"We're the number-one producer in North America. Why would we want to give that up?" McGuinty said.

"We have plants, we have people, we've got sophisticated technologies, we've got know-how -- we've got a demonstrated record of success. So we're not going to give that up, and we'll find some way to move forward with that."

Clement has said Ottawa is preparing for the possibility of bankruptcy by either GM, Chrysler or both.

Clement told CTV's Question Period on Sunday that the government's "plan B" involved preparing to protect the taxpayer-backed loans should the automakers fall into immediate trouble.

Ottawa is also providing up to $185 million to guarantee warranties of GM and Chrysler vehicles, plus another $700 million for hard-hit auto parts manufacturers.

McGuinty didn't say whether how probable he considered the bankruptcy scenario to be, but maintained Ontario will help the sector no matter what happens.

"I just don't want people to equate proceedings inside the court as somehow spelling the end of the industry in Ontario because that's not what it would be about," he said.

With a report from CTV Toronto's Paul Bliss and files from The Canadian Press