A spokesman for the police in the southeastern province of Alicante where Benidorm is located said authorities were investigating the death of the woman, who fell on Saturday morning.
He was unable to give further details, including the woman's age.
But the local Diario Informacion newspaper reported she was 25 years old, and had been partying with other Britons when she fell.
It is not known whether it was an accident or a suicide, or if she was pushed.
A fishing village five decades ago, Benidorm today is a mass of skyscrapers, fast-food outlets, bars and nightclubs where tourists come on cheap package holidays.