One woman who had worked for Fayed at the luxury Knightsbridge store called him "a monster".
Harrods apologised on Thursday after more than 20 women told the BBC Al Fayed had sexually abused and in some cases raped them.
He died in 2023 aged 94.
"Underneath Harrods glitz and glamour was a toxic, unsafe and abusive environment," lawyer Gloria Allred told a news conference.
"I could not believe that this monster had gotten away with his crime," accuser Natacha said. (AP PHOTO)
She said the allegations included serial rape, attempted rape, sexual battery and sexual abuse of minors, perpetrated over 25 years.
Another lawyer, Dean Armstrong, said they were representing 37 women and that number would likely grow.
Natacha is one of them.
"Seeing his obituary just over a year ago triggered such a huge emotion," she told reporters, without giving her last name.
"I could not believe that this monster had gotten away with his crime."
According to a BBC documentary that aired on Thursday, Harrods failed to intervene and helped to cover up abuse allegations during Al Fayed's ownership between 1985 and 2010.
He always denied the accusations.
Lawyer Maria Mulla said once female employees were selected for jobs such as secretary or private assistant, they would undergo medical examinations, such as cervical and ovaries screenings.
"If the women would query why the tests were necessary, they would be told ... he wants to make sure that you are clean," Mulla said.
Workers were threatened if they tried to complain about the abuse, she said.
Harrods said it was "utterly appalled" by the allegations.
"These were the actions of an individual who was intent on abusing his power," Harrods said in a statement.
Lawyers intend to sue Harrods, saying it bears "corporate responsibility" for what happened. (AP PHOTO)
"We also acknowledge that during this time his victims were failed and for this we sincerely apologise."
Al Fayed sold Harrods to the investment vehicle of the Qatar royal family in a deal reported to be worth about Stg1.5 billion ($A3 billion) in 2010.
The department store said it was now a "very different organisation".
A spokesperson for the Ritz hotel in Paris, which Al Fayed also owned, said it "strongly condemns any form of behaviour that does not align with the values of the establishment".
Several media organisations had exposed allegations of sexual abuse against Al Fayed in the past, including Vanity Fair in 1995, ITV in 1997 and Channel 4 in 2017.
Many of the women only felt able to speak publicly after he died.
In 2009, prosecutors decided not to charge Al Fayed over a claim he sexually assaulted a 15-year-old girl in his store, saying there was no realistic prospect of conviction.
Armstrong said Harrods was aware of Al Fayed's behaviour way before 2023 and should have acknowledged it earlier.
Lawyers said victims deserved justice, and they would pursue a civil case against Harrods because of its "collective corporate responsibility" for what happened.
Born in the Egyptian city of Alexandria, Al Fayed built his family's fortune in real estate, shipping and construction, first in the Middle East and then in Europe.
Al Fayed spent 10 years trying to prove Princess Diana and his son Dodi were murdered when their car crashed in a road tunnel in Paris in 1997.
His claims were unsupported by any evidence, according to the inquest into Diana's death.
