Lawyers acting for Sylvia McDermott, who lost her cleaning job at Kensington Palace in November, said they were considering seeking a witness order - the industrial tribunal equivalent of a court subpoena - which would oblige her to attend.
Solicitor Anu Kapoor of Michael, Amy and Partners, who is acting for the maid, said: "The lawyers for the Princess of Wales have confirmed that she will not be attending, so we are considering seeking a witness order.
"If it is granted, then she will be obliged to attend.
"The hearing on Wednesday 5 March is to seek to secure an order that Sylvia McDermott be re-employed by the Princess."
The maid joined the household of the Prince and Princess of Wales in July 1987 and stayed with Diana when the couple separated in 1992. Her duties involved dusting and cleaning the royal apartments.
The dismissal is alleged to have come after two face-to-face meetings with the princess.Reuse content