The former Italian premier is on trial for allegedly paying a 17-year-old Moroccan girl for sex, then using his influence as Italian premier in 2010 to cover it up. He has denied the charges.
State TV quoted witness Imane Fadil as telling the Milan court that two young women at the party wore black tunics, crosses, and white head coverings, danced like "Sister Act" characters, then stripped down to their underwear. Fadil is also Moroccan.
At a different soiree, Fadil testified, a young woman put on a jersey and mask to dress up like Brazilian soccer star Ronaldinho, then took them off to reveal skimpy panties. Ronhadinho used to play for AC Milan, the soccer club owned by Berlusconi.
Prostitution is legal in Italy, but paying for sex with a minor is a crime.
Berlusconi, who resigned in November under pressure from financial markets during Italy's debt crisis, didn't attend Monday's trial session.
Last year, details from prosecutors' documents revealed that a Berlusconi crony purportedly told a young woman to dress up as a sexy nurse and pretend to examine the media mogul as a joke. The same prosecutors' documents claimed that an unidentified person told police that policewomen's uniforms also were available at the parties. That allegation prompted a protest from a police union.
Sessions in the Berlusconi trial are held a few times a month and are scheduled to continue until the end of May. If convicted, the former premier could be barred permanently from holding public office.
He has turned over the formal leadership of his political party to his former justice minister and indicated he might not run for what would be a fourth stint as premier.