The young nightclub dancer at the centre of Silvio Berlusconi's sex trial arrived in court to testify on Monday but the former Italian premier's lawyer asked for the case to be suspended until after elections next month.

Karima El Mahroug, 20, and better known by her stage name "Ruby the Heartstealer", fought her way through a jostling scrum of photographers as she arrived at the court in central Milan where Berlusconi is on trial on charges of paying for sex with a minor.

El Mahroug, who wore a black jacket, black boots and a grey scarf for the court appearance, has stayed out of sight since having a baby girl a year ago with her nightclub owner boyfriend. She kissed him as she arrived inside the courtroom.

El Mahroug had been due to testify in December but failed to show up, telling her lawyer she was on holiday in Mexico. The prosecution alleged this was a ploy intended to delay verdict in the sensational trial.

Niccolo Ghedini, one of Berlusconi's legal team, told the court Berlusconi would be too busy campaigning to follow the case or to attend hearings. He also wanted to avoid the trial being "exploited" against Berlusconi during the campaign, he said.

Ghedini said any development in the trial would have repercussions in the media and the defence wanted "to avoid the possibility of the trial influencing the campaign".

The judges retired to consider the request as the Moroccan-born El Mahroug sat smiling in the courtroom.

Berlusconi is leading his centre-right People of Freedom party (PDL) into national elections on Feb 24-25, although it is still not clear if he will be running for prime minister.

Since he entered the campaign in December he has gradually improved his group's opinion poll ratings but is still far behind the centre-left group that is expected to win.

Berlusconi, 76, is accused of paying Mahroug for sex when she was under 18, which is the minimum legal age for prostitution in Italy.

The billionaire media mogul denies all charges and Mahroug has said she never had sex with him.

The trial, in which dozens of aspiring show girls have described so-called "Bunga Bunga" parties at Berlusconi's residences, is the most sensational of his legal cases and has received huge media attention in Italy and abroad.

Berlusconi is also accused of abusing his powers when he was still prime minister to have Mahroug released from police custody when she was briefly held over theft allegations.

He could be sentenced to up to 15 years in prison but would not serve time unless he also lost the two appeals allowed by Italian law, usually a lengthy process.