Italian Prime Minister Silvio Berlusconi is under investigation for allegedly trying to gag a political talk show that is often critical of him, media reports said yesterday.

Prosecutors in the southern city of Trani launched the probe into Mr Berlusconi as well as a member of the broadcasting commission Agcom, Giancarlo Innocenzi, and the director of news programming for public television channel RaiUno, Augusto Minzolini, the reports said.

Prosecutors reportedly have telephone intercepts in which Mr Berlusconi asked Mr Innocenzi and Mr Minzolini to stop the programme, AnnoZero, hosted by journalist Michele Santoro.

The wiretaps were carried out for a separate investigation into usury and credit card fraud.

The show, which airs on the traditionally pro-opposition RaiTre channel, has explored the sex scandals that have dogged Mr Berlusconi for the past year.

It has also used actors to stage reconstructions of wiretapped phone conversations between mafia figures and politicians including some close to the Prime Minister.

The conservative Mr Berlusconi, 73, faces charges of misappropriation and threatening a political, administrative or judicial body, while Mr Innocenzi is suspected of complicity and Mr Minzolini of communicating confidential information.

Mr Berlusconi's lawyer Niccolo Ghedini slammed the investigation, saying: "The premise is not only devoid of any foundation but contrary to common sense," adding that no corresponding infraction was contained in the penal code.

Dr Ghedini said he suspected that "news leaks" about the probe could be linked to regional elections set for March 28 and 29.

Mr Berlusconi, for his part, said in an interview over public radio that the prime minister should have "the right to speak on the telephone without being overheard, especially without knowing it, as was the case here."