Italy's Financial Guard has been issued a warrant to search the Milan headquarters of Mediaset, Italy's largest private broadcaster, as part of an investigation into possible wrong-doing during Italian premier Silvio Berlusconi's first stint as prime minister in 1994.

The investigation, which the European Union Commission is also conducting, is focusing on TV rights acquisitions and tax breaks which Berlusconi's media conglomerate, Fininvest, would have benefited from during his first seven-month term in government.

Berlusconi, who swept to power for the second time last month after he beat centre-left candidate Francesco Rutelli, continues to face vociferous criticism over potential conflict of interest issues. In an attempt to address these problems, the media magnate-turned politician announced over the weekend that he had drafted a proposal to let a team of three people oversee financial operations at Fininvest.

Berlusconi said the commission, which would be appointed by the country's antitrust watchdog, would not be involved in the day-to-day running of the company. Rather, he said, they would look into "any acts contrary to the public interest".

"I have already drafted a plan of laws to create a commission of three wise men," he told Il Giornale, a right-leaning Milan daily newspaper. It was not immediately clear whether Berlusconi's previous suggestions about establishing a blind trust had been dropped.

Berlusconi has stated several times that he will resolve the conflict-of-interest issue before the annual August summer break. But political opponents remain sceptical about a solution that doesn't involve a sale of Mediaset. Concern has also now been fuelled by reports suggesting that while Berlusconi's proposed trio of advisers would be chosen by Italy's Antitrust Authority, he would still be able to reject nominees.

Fininvest, Berlusconi's holding company, owns 50% of the publicly listed broadcaster Mediaset, which is formed by Rete 4, Canale 5 and Italia 1. As prime minister, Berlusconi now also controls the three-channel RAI network. Both networks together attract around 90% of Italian viewers.