Silvio Berlusconi, who denies any wrong doing, admits he helped release an exotic dancer from prison [REUTERS]

Italian prosecutors have filed a request to seek an immediate trial for Silvio Berlusconi, the prime minister, over claims he paid for sex with an underage girl and then used his position to help her.

Magistrates in Milan made their request for a fast-track trial on Wednesday, after completing an inquiry into allegations Berlusconi paid for sex with a  "significant number of young women" including a 17-year-old nightclub dancer nicknamed Ruby the Heart-Stealer.

They have also accused the 74-year-old premier of abusing his powers to get the Moroccan dancer, whose real name is Karima El Mahroug, out of police custody when she was accused of theft in May.

Berlusconi responded shortly after the request was made, saying the prosecutors are acting "subversively" and that the case was a pretext to oust him.

'Politically motivated'

It is believed that the judges, led by Edmondo Bruti Liberati, the chief prosecutor, have enough evidence to to skip preliminary hearings on both charges.

In a statement on Wednesday prosecutors said they had "sent the examining magistrate a request for an immediate trial on the basis of sufficient evidence" for both offences.

Berlusconi, who along with El Mahroug has denied having sex, has dismissed the claims against him as politically motivated.

He has admitted calling the police to get her out of custody, a move his supporters say he made because he believed at the time she was the niece of Hosni Mubarak, the Egyptian president.

Once filed the examining judge will have five days to make a decision on whether the case warrants a fast-track procedure, meaning a start date could be made before the summer.

However if there is not sufficient evidence for such a process, prosecutors will have to try the usual but more lengthy procedures.

The investigation by Milan prosecutors was made public on January 14, one day after a court partially removed Berlusconi's right to political immunity.

However he has refused to be questioned over the allegations, saying the Milan magistrates are not qualified to handle them.

His lawyers have also said Berlusconi can only be judged by a special court for members of parliament, and have accused the Milan court of "violating the constitution".

The scandal has come as the prime minister faces a number of problems, including a split in his ruling party that has left him in a weakened position, and a drop in popularity.

He also faces the resumptions of three other trials for corruption and tax fraud in the next month.

Despite this, he has resisted calls to step down and recent polls suggest he could still win an early election.