The politician-media relationship has never been perfect, he said Thursday, adding, "I think we need to get it on better footing."
Cameron testified before the Leveson Inquiry, which he set up, examining media ethics in the wake of the phone-hacking scandal that forced the closure of the tabloid The News of the World, a property of global media mogul Rupert Murdoch's News Corp.
He called the inquiry, led by Lord Justice Brian Leveson, a "cathartic moment" for the media, politicians and the police.
Cameron said he thinks regulations are "glossed over" in the current regulatory system, The Daily Telegraph reported.
"We need to improve it," he said.
The relationship has "become a bad one" since a scandal involving lawmakers' expenses and the phone-hacking scandal at The News of the World, Cameron said.
When discussing his meetings with media executives before he became prime minister, Cameron said he probably met with members of the media more than 1,400 times during his five years as opposition leader.
Cameron also noted he has developed long-term friendships with members of the media, including Matthew Freud, Murdoch's son-in-law and head of head of Freud Communications, an international public relations firm based in Britain.
He said he met Rupert Murdoch 10 times and his son, James Murdoch, five times. The prime minister said he also met 19 times with Rebekah Brooks, who was editor at News of the World when the scandal broke, and has been charged in that matter.
When the scandal broke, Cameron's judgment was questioned over his hiring of former News of the World editor Andy Coulson as his communications director. Coulson resigned from his government post last year when police began a new phone-hacking investigation. He had left the News of the World after two employees were jailed over phone hacking in 2007 but denied any knowledge of wrongdoing while he was the newspaper's editor. Coulson was arrested in May and charged with perjury over court testimony about phone hacking.
Meanwhile, London police said they arrested three people as part of an investigation into allegations of inappropriate payments to police and public officials, the Telegraph reported. The arrests were made by officers working on Operation Elveden, which is being run in conjunction with Operation Weeting, the police inquiry into the phone hacking.
The police statement said the arrests resulted from information provided by News Corp.'s Management Standards Committee.