The allegations came Wednesday from the woman's lawyer, Gloria Allred, a longtime Democratic supporter.
Allred says the housekeeper, Nicky Diaz, worked for Whitman from 2000 to 2009, when she was fired. The attorney claims Whitman received a letter from the Social Security Administration on April 22, 2003, saying the Social Security number provided by the housekeeper did not match the name on file.
Diaz said she saw the letter but said Whitman and her husband never asked about her immigration status.
Whitman told reporters Wednesday she never received the letter. She said she fired Diaz in June 2009 when the worker told her she was in the country illegally.