A judge in the northern city of Milan will now have five days in which to decide whether there is sufficient evidence for the case to proceed to trial.
Prosecutors said "there was evident proof" against Berlusconi that he had paid for sex with a Moroccan teenage nightclub dancer nicknamed 'Ruby' who was 17 at the time and that he abused his office to pressure police to release her from custody on an unrelated theft charge.
Milan chief prosecutor Edmondo Bruti Liberati said Wednesday that 'Ruby' whose real name is Karima El Mahroug, was being investigated by a juvenile court for making untrue statements after police detained her on 1 May 2010 for allegedly stealing cash and jewellery from a female acquaintance.
She was released by police following a phone call from Berlusconi, who told them El Mahroug was the niece of Egyptian president Hosni Mubarak.
Prosecutors believe Berlusconi acted to conceal the true nature of his relationship with the teen rather than to "help someone in trouble," as he claimed.
El Mahroug, whose stage name is 'Ruby the Heartstealer' denies having sex with Berlusconi. But she has admitted receiving 7,000 euros from Berlusconi after a party at his villa near Milan, am Audio car and other gifts.
Berlusconi denies the sex allegations, insisting the charges are politically motivated by 'left-wing' judges. He said on Wednesday he would "sue the Italian state" over the sex allegations.
The premier's lawyer, Nicolo Ghedini has accused Milan prosecutors of "violating the Italian constitution" in requesting an immediate trial for Berlusconi over the allegations.
Although having sex with prostitutes is not an offence in Italy, using an underage prostitute is a crime which carries a prison sentence of up to three years.
Berlusconi's legal defence is asking Morocco's authorities to send proof of El Mahroug's date of birth and is expected to argue that she was actually born in 1991 and so was 18 at the time of her alleged sexual relations with the premier, rendering the accusation of no criminal relevance.
Abuse of office is a more serious offence which is punishable by up to 12 years in jail.
Prosecutors have now submitted 782 pages of wiretap transcripts and other documents backing their claims that Berlusconi paid "numerous" young women for sex.
The prosecutors said Monday they were considering widening the prostitution probe to include another suspected underage prostitute who may have spent the night with Berlusconi at his villa in Arcore, near Milan, a Brazilian named Iris Berardi.