Labour concession talks between General Motors and the Canadian Auto Workers likely won't come to a successful conclusion Monday, according to sources from both sides.

Sources told CTV Toronto that the two sides will keep on negotiating but they are currently too far apart to reach a deal tonight.

The main point of contention continues to be around the workers' pension funds.

CAW President Ken Lewenza said late Monday that he expected talks to go late into the night and start again on Tuesday.

"We haven't made much progress, so we're still at it," Lewenza told The Canadian Press. "No change since the last report -- we're still bargaining.

"We believe we've already made the sacrifices necessary, we believe we're close to our limit,"

The talks resumed Monday morning after adjourning early Sunday evening to give both sides a rest after two late nights of negotiations.

The CAW and GM have been given more time to work out a deal after they missed a government-imposed deadline of midnight Friday.

Both sides are being urged by the government to stay at the bargaining table and hammer out a deal.

GM must submit viable restructuring plans to the federal and Ontario governments, as well as U.S. authorities, in order to receive billions of dollars in bailout funds.

The two sides did reach a cost-saving agreement in March that would have reduced total labour compensation by $7 per hour, or about 10 per cent. However, both the federal and Ontario governments said the terms did not go far enough and sent the two sides back to the drawing board.

Lewenza said the union's goal is to make cost-saving concessions without affecting wages, benefits or pensions.

On Monday, he said the negotiations have made him feel like he's "walking in quicksand."

"It's slow and it's methodical," he said.

The union had offered to cut the same deal it had with Chrysler, which resulted in a total compensation cut of $19 per hour, or about 25 per cent. But Lewenza has said that GM wants further concessions.

Lewenza said that a deal still needs to be reached around wages and benefits, as well as a $7 billion shortfall in the company's pension fund.

"What's difficult about a defined pension plan is the employer was supposed to be making a contribution during the days that the people were working in the plant," he said. "It's not possible to deal with that kind of retroactivity at the bargaining table."

GM Canada employs 7,500 hourly workers at a car plant in Oshawa, Ont., a transmission plant in Windsor, Ont., and an engine plant in St. Catharines, Ont. It also operates CAMI, an SUV plant in Ingersoll, Ont., which is a joint venture with Suzuki.

Last Thursday the company closed a truck plant in Oshawa, while the Windsor factory is scheduled to close next year.

With files from The Canadian Press