Education Secretary Michael Gove warned today warned against letting "judges, celebrities and the establishment" take over as the arbiters of where the limits of free speech should be set.
Speaking during a lunch for Lobby journalists he also questioned the need for additional regulation of the press, saying that existing laws were already in place to deal with wrongdoing by "rogue" reporters.
The Education Secretary - formerly a journalist on the News Corp-owned Times - said he saw "dangers" in the inquiry into press cultures, practices and ethics chaired by appeal court judge Lord Justice Leveson, which was commissioned by David Cameron last year in the wake of claims of phone-hacking at the News of the World.
Gove said: "It is undoubtedly the case that there were serious crimes which were committed, but we know that these crimes were serious because they broke - if the allegations are proved - the already existing criminal law.
"There are laws against the interception of messages. There are laws against bribery. There are laws which prevent journalists - like any other profession - going rogue. Those laws should be vigorously upheld and vigorously policed.
"However, there is a danger at the moment that what we may see are judges, celebrities and the establishment - all of whom have an interest in taking over from the press as arbiters of what the free press should be - imposing either soft or hard regulation on what should be the maximum of freedom of expression and the maximum of freedom of speech."
Gove warned: "Politicians should recognise that we have nothing to gain and everything to lose from fettering the press, which has helped keep us honest in the past and ensured that the standards of debate are higher in this country than in other jurisdictions."
He acknowledged that there were times when he had taken exception to press coverage of his activities.
But he added: "I want to concentrate on the big picture and the big picture is that there is a chilling atmosphere towards freedom of expression which emanates from the debate around Leveson.
"I think there are laws already in place which we should respect and principles already in place that we should uphold which are central to making sure that this country remains free."
Gove said that the Leveson Inquiry came at a particularly difficult time for the UK's newspapers, which are fighting falling sales and advertising revenues as a result of new competition from the internet and other news sources.
"That is why whenever anyone sets up a new newspaper - as Rupert Murdoch has with the Sun on Sunday - they should be applauded and not criticised, and why journalists should be more assertive in making the case for press freedom," he said.
Cameron's spokesman told reporters: "The Prime Minister set out his position on Leveson at the time he set up the inquiry. He has made very clear on a number of occasions since how important he thinks it is that we have a free press and free media that is able to challenge governments and others."
Asked whether the PM shared Gove's concerns about the impact of the Leveson Inquiry on press freedom, the spokesman said: "There is a public inquiry and, having set up a public inquiry, you would expect us to see what the conclusions were before taking any further actions."