The 32 witnesses will be placed under investigation in September, when Milan, Italy, judges issue their explanation for the Berlusconi's guilty verdict, the Italian news agency ANSA reported Tuesday.
Berlusconi, 76, was convicted Monday of paying Karima "Ruby" El Mahroug for sex, and abusing his office to cover it up. He was sentenced to seven years in prison and banned from public office, a conviction his lawyers say he will appeal.
The three judges in the case said they asked prosecutors to investigate suspicions defense witnesses lied during the trial in an attempt to help Berlusconi, the British newspaper The Daily Telegraph reported.
El Mahroug, a former nightclub dancer known as "Ruby Heartstealer," did not testify and it not on the list of witnesses.
Supporters of former Italian Premier Silvio Berlusconi plan to protest his seven-year prison sentence. A front-page headline in a right-leaning newspaper called the sentence "shameful" and said it lowers Italian justice to the level of "Afghanistan or Iran," ANSA reported.
Members of his center-right People of Freedom party occupy important seats in Italy's left-right coalition government, and have vowed to resign en masse if their leader's ban from office is upheld at the Supreme Court of Cassation.