Italian prosecutors have requested that former prime minister Silvio Berlusconi be tried for tax fraud in what would be a fifth trial against the flamboyant billionaire, legal sources said.

Berlusconi, 75, should face trial with 11 others as part of an investigation into film distribution rights and television stations owned by his family, sources in the Rome prosecutor's office said. He has denied the charges.

Berlusconi is already on trial for tax fraud in one of his four trials in which he is also defending himself against charges of bribery, sex with an underage prostitute and abuse of office, and violation of official secrets.

Prosecutors in Milan on Wednesday requested a five-year jail term for Berlusconi as his bribery trial there draws to a close, prompting a furious reaction from Berlusconi who said he was the victim of "judicial persecution".

Even if convicted, Berlusconi is unlikely to ever see the inside of a cell because of the combination of Italy's lengthy appeals process and the statute of limitations and because sentencing guidelines are lenient to over-70s.

The charges levelled on Thursday relate to transactions made in 2003 and 2004 by Mediatrade-RTI, a subsidiary of Berlusconi's Mediaset company.

Prosecutors alleged that Mediatrade-RTI artificially inflated the broadcasting rights for films before selling them on to Mediaset.

The alleged financial mechanism allowed the company to build up foreign slush funds and to lots its declared revenue in Italy to dodge taxes.

Prosecutors have also requested a trial for Mediaset chairman Fedele Confalonieri and deputy chairman Pier Silvio Berlusconi, the ex-PM's son.