A combo shows file photos of Karima El Mahroug of Morocco posing in Milan, and Italy's former Prime Minister
Karima el-Mahroug, aka Ruby the Heart-stealer and Italy's former prime minister Silvio Berlusconi (Reuters)

Ruby the Heart-stealer, the go-go dancer who was due to appear as a defence witness in the "bunga-bunga" trial of former PM Silvio Berlusconi, has disappeared, according to reports.

The attorney for Ruby, whose real name is Karima el-Mahroug, told the court in Milan that she was abroad and could not be contacted.

Prosecutor Ilda Boccassini said the witness's absence was not justified and asked the court to instruct detectives to find her.

Boccassini accused Berlusconi's lawers of hijacking the trial.

"I do not believe in what the defence lawyer said," Boccassini argued. "It's just a strategy to postpone the trial to the beginning of the electoral campaign."

Berlusconi's lawyer, Niccolo Ghedini, in turn said the prosecutors were trying to hasten a verdict before the election. "It is the magistrates who have started the election campaign," he told reporters outside the court.

The judge ordered police to search for el-Mahroug "throughout the national territory" and the trial was adjourned to December 17.

"I tried reaching her but her cellphone is off. She sent me a text saying she was abroad but I have no information about this trip and I don't know when she will be back," el-Mahroug's lawyer, Paola Boccardi, said.

Berlusconi, who declared that he would run for office again after incumbent prime minister Mario Monti said he would step down, is on trial on charges of underage prostitution and exaction (bribery) charges. Ruby was 17 at the time.

Shortly after they allegedly met, Ruby was arrested, Berlusconi famously called the police station putting pressure for her to be released, claiming Ruby was former Egypt president Hosni Mubarak's granddaughter and that her detention could have caused a diplomatic incident. At the time Berlusconi was Italy's Prime Minister.

Because of the incident Berlusconi is charged with using his power for personal gain - a crime in Italy.

In a separate case, which ended in October, Berlusconi was convicted of tax evasion and sentenced to four years in prison and barred from holding public office for five years. He will not serve his sentence, however, until an appeal court ruling.

Critics say that Berlusconi's comeback announcement is a deliberate move to shore up his reputation and delay the outcome of his trials.

Earlier in December, Berlusconi's former mouthpiece, Emilio Fede, told a court that Ruby "was ugly and stank".

Fede, who has been the editor of Berlusconi's Rete 4 TV station newscast TG4 for 20 years, denied that he was the one who introduced the underage escort at Berlusconi's Arcore Villa.

According to Italian prosecutors, Fede was aware that Ruby was underage when she attended Berlusconi's parties. He denied the claim.