The British Red Cross is attempting to claim £10,000 from a former member of staff who took it to an employment tribunal.
Jackie Rutherford alleged she was unfairly dismissed and suffered race, age and disability discrimination. Rutherford, who is now unemployed and has a disabled husband, lost the hearing in Stratford, east London, last month.
She has now received a letter from the charity saying it has applied to the tribunal for £10,000 in costs.
In a statement, the British Red Cross said it wanted to partially cover the organisation's financial loss in court fees and staff time. Martyn Dicker, human resources manager for the south east at the charity, said it had made every possible effort to prevent the case coming to court and had warned Rutherford that it would seek to cover its costs.
"The case cost British Red Cross more than £10,000 in legal fees and staff time," said Dicker. "This money could have been spent delivering vital services to vulnerable people in crisis.
"As a charity, we have a responsibility to our beneficiaries, and it is for this reason only that we are attempting to recoup some of that loss."
Rutherford, a service assistant, was made redundant last year during a restructure of the charity's London operation. She refused to apply for other positions in Kent, claiming they were too far from her Essex home.
She told Third Sector she had no means of paying the costs and her church was trying to find legal advice to help her contest the application.
"How am I going to pay it? I am unemployed," she said. "They are taking the mickey." The threat of costs was likely to deter people from going to tribunals, she added.