Berlusconi, 76, is accused of paying a 17-year-old Moroccan prostitute to have sex with him during what prosecutors have described as a rapacious days-long sex party. In Italy, women must be 18 to engage in prostitution.
The ANSA news agency said prosecutors said they have telephone records that place the teen at Berlusconi's villa from April to May 2010, when one of Berlusconi's so-called "bunga bunga" parties took place.
Both he and the girl deny they had sex.
Prosecutors said Berlusconi had sex with as many as 33 alleged prostitutes in several days, another charge Berlusconi denies.
Berlusconi is also standing trial on allegations of tax evasion at his media empire Mediaset.
The prostitution trial is set to resume Wednesday. The tax evasion trial is set to resume May 13. Both are taking place in Milan.
The former prime minister has maintained the allegations are politically motivated.