Introducing a new parliamentary bill to regulate newspapers would "open a Pandora's box" which could stifle freedom of speech, the chairman of the Press Complaints Commission (PCC) has warned.
Lord Hunt of Wirral told the Leveson Inquiry that many MPs and Lords have told him they would try to use any legislation to control the press, the Press Association reported.
The Conservative peer, who became PCC chairman in October, said his 35 years in Parliament had taught him to oppose any form of statutory regulation of newspapers.
He told the hearing: "There are very strong views in Parliament that there must be stronger limits on the power of the press, and this would therefore in my mind open a Pandora's box.
"It would be, for many of my colleagues in Parliament, a wonderful moment if they were given the opportunity to move amendments to debate a bill regulating the press, and I just do not know what would emerge the other side.
"We were determined that what would emerge the other side of the 2005 Act was the independence of the judiciary. There is no such agreement about the independence of the press."
He added: "The road to parliamentary hell is paved with good intentions."
Inquiry chairman Lord Justice Leveson asked him: "Do you think that Parliament might seek to use any form of legislation, however it was cast, as a way of controlling the press?"
Lord Hunt, a former MP who served as a Cabinet minister under Baroness Thatcher and Sir John Major, replied: "Yes, and they have told me so, many of them in both houses.
"And that is what is driving me forward to find a solution and to respond positively to your own comments right at the outset of this... that there is a wonderful opportunity for the press itself to put its own house in order."
He said the PCC in its current form is not a regulator in the sense called for by Sir David Calcutt in his second report into the self-regulation of the press, published in 1993.
Lord Hunt proposed turning the PCC into a true regulator of newspapers, with separate arms for dealing with complaints and enforcing standards.
He said publishers would have to sign up to the new body on a five-year rolling contract.
"I have come to the conclusion that we do urgently need a fresh start and a totally new body with substantially increased powers to audit and enforce compliance with the code, to require access to documents, summon witnesses when necessary and also to impose fines, all backed by the commercial contracts," he told the inquiry.
Meanwhile, his predecessor Sir Christopher Meyer issued a strident defence of his record as PCC chairman from 2003 to 2009 and insisted Britain's newspaper regulation system was "as good as you're going to get".
He was scathing about a suggestion that the PCC should have exercised stronger leadership to prevent newspapers printing libellous stories about Madeleine McCann's parents and Christopher Jefferies, who was wrongly arrested over Joanna Yeates's murder.
He told the inquiry: "It's as if you would say to the police, 'you're a useless organisation because you can't stop crime' or you would say to the bishops, 'we still have sin after all these years, you had better give up and go'.
"It's a ridiculous set of arguments. As long as there are human beings involved, there will be that fallibility."
Sir Christopher, former press secretary to prime minister John Major and British ambassador to Washington DC, rejected a picture of the PCC as "an inert, inactive organisation, sitting there slackly, mouths hanging open".
He rejected suggestions from Robert Jay QC, counsel to the inquiry, that his response to the jailing of News of the World royal editor Clive Goodman in 2007 for phone hacking was inadequate.
He said: "The idea that we should work on the assumption - because this is what you are saying - that the police inquiry was inadequate and we needed to add to the efforts that they had made by sending some kind of quasi-police force into the News of the World, I have to say Mr Jay is entirely fanciful."