General Motors Corp Headquarters is seen along the Detroit River in Detroit, Michigan September 17, 2008. REUTERS/Rebecca Cook

DETROIT (Reuters) - General Motors Corp is suspending matching payments to employee 401K plans as of November 1 and continues to assess its staffing needs as part of efforts to conserve cash amid a deep downturn in sales, the automaker said on Thursday.

GM spokesman Tom Wilkinson said the company could reinstate matching payments into the 401K program if business conditions improve.

The No. 1 U.S. automaker, which has lost $51 billion over the past three years, said in July that it would raise $15 billion in liquidity through 2009 through a series of steps, including a 15 percent reduction of salaried workers in North America.

GM said it did not have a final tally for its salaried workers who have taken early retirement and buyout packages. It declined to comment on whether it would need involuntary layoffs to meet the target for workforce reductions.

GM’s U.S. sales through September were down 18 percent from a year earlier, hit by tightening credit, a slowing economy and a housing market slump, and its ability to ride down the downturn has come under increasing scrutiny.