Rupert Murdoch's dominant position in the British media landscape must never be repeated, British Business Secretary Vince Cable warned last night.
Mr Cable said the impact on media plurality and the political sphere had been "deeply unhelpful".
He also insisted there were "big questions" over whether Murdoch's empire was fit to control a UK broadcaster in the wake of the voicemail-hacking scandal.
The comments came as the British government prepared to publish details of senior ministers' contacts with News Corporation figures over the past 14 months.
Mr Cable was stripped of responsibility for deciding the fate of the firm's bid for full ownership of BSkyB last year after he was recorded in a newspaper sting saying he was at "war" with Mr Murdoch.
Interviewed on the BBC's Andrew Marr show yesterday, the Liberal Democrat stressed there was nothing "personal" about recent concerns raised about the media mogul.
"The balanced historical view would be that he has made positive contributions," he said.
"But we are dealing with the world as it actually is, where we have had a very, very dominant media company and we need to deal with the lessons from that."
He added: "There are other big media companies that could have the same influence in future and we have got to stop that happening."
Mr Cable said it was right that regulator Ofcom should look at whether News Corp's UK subsidiary News International was "fit and proper" to hold a stake in BSkyB.
"Certainly that is a big question to ask in view of what has happened, but fortunately it's not for politicians to come to a definitive judgment on that, it is for the regulator," he added.
Meanwhile, aides to George Osborne have denied any impropriety after it emerged that the chancellor dined with Mr Murdoch in New York in December, shortly before Mr Cable was stripped of responsibility for the BSkyB bid.
They stressed that BSkyB was not discussed, and the visit was wide-ranging.
Elsewhere, it also emerged yesterday that the FBI has started a review of whether alleged phone hacking and bribery by Mr Murdoch's media empire violated US laws.
But any resolution may well have to await the outcome of British investigations.