Prosecutors in Milan have called for the three-time former premier to be banned from politics for life and serve six years in jail in a case which has embarrassed both Berlusconi and his allies.
While a guilty verdict would not mean prison – no sentence would be enforced until the appeals process has been exhausted – it could be a blow humiliating enough to weaken his political influence.
The trial relates to crimes allegedly committed in 2010 when Berlusconi, 76, was prime minister, and revolves around what prosecutors say were erotic parties held at his luxury residence outside Milan.
Berlusconi is accused of paying for sex on several occasions with Moroccan-born Karima El-Mahroug, a then 17-year-old exotic dancer and busty glamour girl nicknamed “Ruby the Heart Stealer”.
But in what the prosecution considers a far more serious charge, he is also accused of having called a police station to pressure for El-Mahroug’s release from custody when she was arrested for theft.
His defence claims he believed El-Mahroug was the niece of former Egyptian president Hosni Mubarak and wanted to avoid a diplomatic incident, but prosecutors say it was a bid to conceal their liaison.
They have called for Berlusconi to spend five years in jail for abuse of office, and another year for paying the dancer for sex after racy “bunga bunga” evenings in a basement room of his mansion.
Both the flamboyant billionaire and El-Mahroug deny having had sex and neither is expected in court on Monday.
The ageing party lover’s fate lies in the hands of three female judges.