Former Italian prime minister Silvio Berlusconi has been sentenced to seven years in jail and a lifetime public office ban by a Milan court in the so-called "bunga-bunga" trial.

The panel of three women judges, chaired by judge Giulia Turri, found Berlusconi guilty of paying a Moroccan teenager for sex and then abusing his position in trying to cover it up.

Judges went over prosecutors' requests after Ilda Boccassini, who led the prosecution team, demanded a six-year jail term for Berlusconi.

"Young girls invited to Arcore were part of a system of prostitution organised for the pleasure of Silvio Berlusconi," Boccassini said in her closing arguments in May.

Berusconi was being tried for allegedly paying 17-year-old Karima el-Mahroug, aka Ruby the Heart-stealer, for sex during the infamous bunga-bunga parties held at his Milanese villa of Arcore.

He was also accused of abusing power by calling a police station, where she was being detained on theft charges in May 2010, to put pressure on detectives to release her.

Berlusconi infamously told authorities that Ruby was a granddaughter of Egyptian president Hosni Mubarak and that her detention could cause a diplomatic incident. He was prime minister at the time.

Berlusconi and Boccassini were not in court as the sentence was read.

Berlusconi's lawyer Niccolo Ghedini said the sentence was "not surprising" and accused Milan judges of bias against Berlusconi.

"It [the ruling] is beyond reality," Ghedini said, adding that they will lodge an appeal.

Berlusconi has often lamented being the victim of political persecution by a group of "red robes" or "communist magistrates" he believes Boccassini is part of.

It is the second sentence to be handed down to Berlusconi in recent weeks. In a separate case, an appeal court upheld a four-year jail sentence and five-year ban from public office for tax fraud.

The sentence cannot be put into effect until two appeals are heard.