Tony Blair has said the media can operate like "a feral beast" and its relationship with politicians is "damaged" and in need of repair.
Tony Blair leaves office at the end of June
The prime minister said relations had always been fraught, but now threatened politicians' "capacity to take the right decisions for the country".
The arrival of web-based news and blogs and 24-hour television news channels meant reports were "driven by impact".
Mr Blair also said newspaper and TV regulatory systems needed to change.
In a speech to the Reuters news agency on public life, he said the media world was becoming more fragmented, with the main BBC and ITN bulletins now getting half the audiences they had previously and newspapers fighting for their share of a "shrinking market".
He said fierce competition for stories meant that the modern media now hunted "in a pack".
"In these modes it is like a feral beast, just tearing people and reputations to bits, but no-one dares miss out," he said.
The result was that the media was increasingly "and to a dangerous degree" driven by "impact" which was, in turn, "unravelling standards, driving them down," he said.
Mr Blair, who will step down as prime minister on 27 June, admitted that New Labour's own attempts to "court" and "assuage" the media in the early days of his government may have contributed to the problem.
He said he had tried to have a dialogue with the media, through measures like on-the-record lobby briefings, monthly press conferences and the Freedom of Information Act.
But, he said: "None of it to any avail, not because these things aren't right, but because they don't deal with the central issue - which is how politics is reported."
He said people in public life, from politics to business, sport, the military and charities, found that "a vast aspect" of their job now was coping with the media, "its sheer scale, weight and constant hyperactivity. At points it literally overwhelms".
And he said there was increasingly commentary on the news, which could prove "incredibly frustrating".
Expecting to be rubbished
"There will often be as much interpretation of what a politician is saying, as there is coverage of them actually saying it," he said.
The current regulatory system, in which broadcasters and the press were subject to different rules and bodies, would need revision, he said, as internet broadcasting blurred the line between TV and newspapers.
And he said the relationship between public life and the media was in need of repair.
"The damage saps the country's confidence and self-belief, it undermines its assessment of itself, its institutions and above all, it reduces our capacity to take the right decisions, in the right spirit for our future."
Mr Blair concluded his speech by saying he had made it "after much hesitation" and he expected it to be "rubbished in certain quarters", but it "needed to be said - so I've said it".
The associate editor of the Sun newspaper, Trevor Kavanagh, said Mr Blair's comments were rather "sour" and "ill-advised" and out of character.
He added that Mr Blair and his government had received the most benign coverage of any leader in recent years.
That benign coverage only changed after the self-confessed "mistakes" made in putting the case for the Iraq war, not because of any change in the way the media operated, he said.
Liberal Democrat culture spokesman Don Foster said: "It's easy to blame the press for a loss of trust in politicians; a fairer analysis would point to his own culture of spin.
"Hints at the need for increased regulation of the press are deeply worrying. Politicians may not like what is sometimes written about them, but a free press is the best safeguard for accountability and against corruption and hypocrisy."