Walter Veltroni, the deputy leader of the winning Olive Tree coalition, who is tipped to take a leading role in the broadcasting reforms, told the Independent that the new government, expected to take office in the next three weeks, wanted to settle the media ownership issue by the summer holidays.
Both Mr Berlusconi's Fininvest empire and the Rai state broadcasting service would be cut back from three network channels to two; tenders would be put out to new private investors and rules would be drawn up to encourage and regulate cable and satellite programming.
"Nobody will be allowed more than two channels," Mr Veltroni said.
"That is what the Constitutional Court has decreed in a ruling which must be respected by August at the latest, and that is what Fininvest and I decided in the agreement we worked out last summer."
The move is likely to be fiercely contested by Mr Berlusconi, who has battled to keep control of his media empire despite his entry into politics and who felt vindicated when he won a series of referendums on media ownership last summer.
A radical reorganisation of Italian broadcasting could interfere with Mr Berlusconi'splans to float his media interests on the Milan stock exchange by the end of June. Since the referendums Mr Berlusconi has regrouped his media companies into a new company called Mediaset and has sold roughly 30 per cent to Italian banks and foreign investors.
The chairman of Mr Berlusconi's business empire, Fedele Confalonieri, said earlier this week that he had been assured by the country's leaders that "our firms will not be dismantled", and that the company was a national asset.
But this is not a view shared by many financial analysts, who argue that the creation of Mediaset and the ensuing share sell-offs have merely enabled Mr Berlusconi to attract new capital without relinquishing overall control.
Mr Veltroni was confident the new legislation would pass without excessive protest from Mr Berlusconi, who is now leader of the opposition.
"The Constitutional Court ruling would have forced him to lose one channel anyway. It's in his interests to find a solution," Mr Veltroni said.
"We have no intention of starting a witch-hunt or provoking confrontations."
The new government also hopes that Rai, whose programme output has come to resemble Mr Berlusconi's blend of cheesy game-shows, films and imported serials, will return to its original role as a genuine public service.
Mr Veltroni said he hoped the new board of management at Rai, which must be approved by the new parliament, would reintroduce educational and cultural programmes which had been slowly squeezed out over the past 10 years.
"We want to take the politics out of programming and create a body that promotes quality," he said.