Sharon Terlep / The Detroit News

General Motors Corp. CEO Rick Wagoner said Thursday that the company could have to shutter more U.S. factories or eliminate shifts at plants to bring the automaker’s production in line with declining demand for cars and trucks in its home market.

He didn’t say how many plants will close or whether GM has decided which facilities to shutter, but said the closures will include powertrain and stamping factories as well as assembly plants. Additionally, Wagoner said the company will offer buyouts to 46,000 of its 72,000 blue collar workers. GM wants to cut costs by about $5 billion by 2011.

GM will extend buyout offers to its entire U.S. work force next month and usher the workers out in April. GM hasn’t announced how many workers it will accept from those who are eligible.

The buyout terms are expected to be similar to the 2006 incentives when more than 34,000 hourly workers left the automaker in exchange for packages ranging in value from $35,000 to $140,000.

GM last month offered buyout incentives to 5,200 of its workers.

GM wants to clear out veteran workers to make way for new employees that would largely be hired at a second-tier wage level for about half the current average pay. GM won the right to establish two-tier wages in this year’s national contract talks with the UAW. New workers who have jobs considered non-core to building cars and trucks would start at about $14 an hour and have less expensive benefits packages.

In a presentation to Wall Street analysts, Wagoner said the company has "exceeded expectations on virtually all counts," of the sweeping restructuring plan laid out in 2005. Wagoner said the automaker has cut $9 billion in annual operating expenses and made measurable gains in the look and quality of its cars and trucks.

The company plans to further reduce its structural costs as a percentage of revenue, with a goal of 23 percent by 2012, down from 34 percent in 2005.

GM will likely again lose money on its North American operations in 2008, Chief Financial Officer Fritz Henderson said. He said financial pressures in GM’s home market will "abate somewhat" in 2010, but didn’t say whether GM expects to make money that year.