Italian prosecutors have asked that Prime Minister Silvio Berlusconi face trial immediately over accusations that he paid for sex with an underage girl and used his political authority to try to cover it up.

Prosecutors filed the request in Milan on Wednesday. They are hoping for a trial as soon as possible because they believe they have gathered overwhelming evidence against Berlusconi.

The 74-year-old Italian premier described the legal action as "disgusting" and politically motivated. Berlusconi spoke to reporters in Rome, calling the request for an indictment an attempt by prosecutors to damage his government.

"It's shameful, really," Berlusconi said of the prosecutors' move. "It's shameful and disgusting."

Suggesting that the allegations had "offended the dignity of the country," Berlusconi asked: "I wonder who's going to pay for these activities that, in my humble view, only have a subversive aim?"

In an interview from Rome, Globe and Mail reporter Eric Reguly said prosecutors take a different view.

"They have been looking at this for six months and they have evidence as thick as a phone book against him," Reguly told CTV's Canada AM.

Prosecutors filed their request in Milan Wednesday, asking for the 74-year-old prime minister to stand trial immediately on two charges.

They want Berlusconi indicted on charges he paid for sex with 17-year-old Karima El Mahroug, a Moroccan nightclub dancer widely known by her nickname Ruby, and then used his position to free her from police custody on suspicion of an unrelated theft.

The judge, Cristina Di Censo, now has five days to decide whether there is sufficient evidence to indict Berlusconi or dismiss the request outright. If the request is granted, prosecutors can skip the preliminary-hearing phase and go straight to court.

Word of the request reached Berlusconi as he was holding a news conference to outline his plans for a series of reforms aimed at kick-starting the Italian economy.

Berlusconi has vehemently denied any wrongdoing in the case, conceding that he intervened out of pity and a misunderstanding about "Ruby" being Egyptian President Hosni Mubarak's niece.

Ruby, who has since turned 18, says she introduced herself as a 24-year-old Egyptian when she first met Berlusconi. Both have denied having sexual relations.

While paying for sex with a prostitute is not a crime in the country, it is if the prostitute is under the age of 18.

If Berlusconi is put on trial, he could face six months to three years in prison for child prostitution, and up to 12 years in jail for abuse of influence.

Italian newspapers have taken great relish reporting Berlusconi throws wild parties featuring topless girls and sexually-enticing dancing at his villas, including the one in Arcore, just outside Milan.

But the premier maintains his dinner parties have only been elegant and dignified.

Last month, Italy's top court effectively stripped Berlusconi's prime ministerial immunity in a ruling that individual judges should decide whether to put him on trial.

The prime minister's defence team says the case should be handled by a special three-member Tribunal of Ministers geared to dealing with accusations against public officials. Prosecutors argue the alleged crimes were committed outside the purview of the premier's official duties.

Noting this case is not Berlusconi's only legal trouble at the moment, Reguly said the premier is famous for avoiding prosecution that has, until now, focused on his dealings as a media mogul.

"He's got an army of lawyers," Reguly said. "He just keeps squirming away. He's like the ‘Teflon prime minister.'"

A trial in which Berlusconi faces charges for allegedly paying his British tax lawyer US$600,000 to lie under oath is due to resume on March 11. Another trial involving alleged tax fraud over TV rights is slated for the end of February.

Yet polls suggest the political damage to Berlusconi has so far been minimal.

"His popularity is down, but not out," Roberto D'Alimonte, a professor of political science at LUISS university in Rome, told The Associated Press.

"One of the main reasons is a lack of clear alternative. On the other side, there is not a single credible coalition, there is not a single credible leader and not a single credible program."

With files from The Associated Press