The porter told The Guardian Savile used staff bedrooms reserved for hospital surgeons and nurses for his assignations.
Porter Terry Pratt said Savile would come in early in the morning about two times a week with different pairs of girls, "one on each arm," in 1981 and 1982.
"They were definitely in their teens," Pratt said. "When they started talking to you it was obvious they weren't streetwise, especially being out at that time in the morning."
The name of a doctor accused of collaborating with Savile has been reported to Scotland Yard, which is investigating Savile.
A former nurse at the hospital said earlier this month Savile had molested a brain-damaged female patient.
Scotland Yard is said to be following 400 lines of inquiry into claims Savile abused 300 children and young people in a period of six decades, The Daily Telegraph reported.
Savile died last October at the age of 84.