By David Willey
BBC Rome correspondent
The Italian parliament has passed a controversial bill aimed at resolving a perceived clash between the public and private roles of the prime minister.
Prime Minister Silvio Berlusconi is one of Italy's wealthiest businessmen and owns a media empire which controls 95% of Italy's commercial TV channels.
Silvio Berlusconi has denied any wrongdoing
Under the new law, Italian politicians will not be barred from owning companies, but they will have to have to hand over managerial control of their businesses, and make their interests public.
Unlike Britain or the United States, Italy has never had any legislation limiting the financial assets and business interests of the prime minister or head of the executive branch of government of the day, to ensure that there is no confusion between his private and public functions.
A conflict of interest bill has been see-sawing back and forth between the two houses of parliament for three years now without every getting passed into law.
Now, suddenly, with the country on the brink of a political crisis, as Mr Berlusconi's coalition partners are threatening to bring down his government, the bill has finally become law.
The new law was immediately denounced by the opposition as a toothless effort to contain Mr Berlusconi's seemingly boundless political and financial ambitions.
Luciano Violante, a leading opposition figure, said the new law contravenes EU directives and says he will report this to Brussels and to the European Parliament.
The opposition is also uneasy about the prime minister taking over the functions of finance minister, since the forced resignation of Giulio Tremonti last week.
Cannot this also be regarded as a conflict of interest, they have been asking. Mr Berlusconi has no obligation under the new law to dispose of any part of his huge media empire.
The only question mark now hangs over the legality of his continuing in office as president of the AC Milan Football Club, a post he has held for 18 years.
A reminder that the Italian prime minister is not yet beyond suspicion of wrongdoing in his financial affairs came with reports of yet another police search of the offices of his media company, Mediaset, in Milan.
Mr Berlusconi's son and daughter by his first marriage, who hold top executive positions in Berlusconi family-controlled companies, are also included in ongoing investigations for suspected fraud and embezzlement, according to court officials.
Mr Berlusconi has vigorously denied any wrongdoing.