Egyptian billionaire Al Fayed died last year aged 94 after decades making newspaper headlines as one of Britain's best known businessmen.
The BBC documentary said he had sexually abused female staff at Harrods in London and had threatened them if they tried to complain. It said Harrods had failed to intervene and helped to cover up abuse allegations during his ownership.
Harrods, which Al Fayed sold in 2010, has said it is "appalled" by the allegations and that it is now a "very different organisation".
Police called last month for anyone with allegations against Al Fayed to contact them and said it would look to prosecute others after the accusations.
"Detectives have received numerous pieces of information, predominantly relating to the activities of Mohamed Al Fayed but some relating to the actions of others," said Stephen Clayman, head of specialist crime at London's Metropolitan Police.
The new allegations relate to 40 victims and cover offences including sexual assault and rape from 1979 to 2013, police said.
They are in addition to 21 allegations about Al Fayed made before the documentary. They were reported to the police between 2005 and 2023 but no action was taken against him.
Al Fayed always denied the accusations.
On Thursday, the BBC announced 65 women had come forward to them about assault allegations since the documentary aired.
While most of the new information concerns his ownership of Harrods from 1985 to 2010, police are contacting other organisations linked to him to ensure anyone affected is identified, they said.
Harrods did not immediately respond to Reuters' request for a comment on Friday's police announcement.
with PA
