MG Rover workers face the threat of having to pay thousands of pounds for cars they have leased from the company.
Employees at the Longbridge factory in Birmingham were told they may be liable for loans taken out to buy new MG Rover cars.
Julie Kirkbride, who is standing for re-election as Conservative MP for Bromsgrove, said she knew of some workers who had five MG Rover cars in their family bought under a special employee scheme.
"It was bad enough that workers face losing their job but this is another bitter blow," she said.
The Transport and General Workers Union was studying agreements on car sales which its members had signed.
A two page memo given to line managers at Longbridge yesterday spelt out that cars were sold to workers via a loan either with a bank or with MG Rover.
At the end of the loan period or after 10,000 miles or after a period of up to a year, the car is normally returned to Rover and replaced by a new car, and a new loan, with the company settling any outstanding finance.
Steven Pearson, joint administrator at PricewaterhouseCoopers, said a special helpline had been set up to address employees' concerns.