Rupert Murdoch's UK newspaper group, News International, faces three probes over allegations that its staff hacked into the mobile phones of celebrities and sports stars.
The director of public prosecutions, the Commons select committee and the Press Complaints Commission have all begun investigations into the claims, the Guardianreports.
The paper reported earlier this week that News International had paid more than Â£1 million ($1.64 million) in out-of-court settlements to cover up phone hacking conducted by freelance private investigators hired by the publisher.
The settlements relate to a 2006 scandal in which it was revealed that News International journalists had hired investigators to hack into mobile phone accounts of celebrities and politicians, The Guardian reports.
But the Metropolitan Police said Scotland Yard would not re-open its investigation, as it was satisfied with the results of an earlier inquiry.
The opposition Conservative Party has also come under fire for hiring Andy Coulson, former editor of News International publication News of the World, as its Director of Communications.
Coulson has always maintained he was unaware that phone hacking took place, but resigned as editor after the claims surfaced.
News International said in a statement it was "inappropriate to comment at this time."
One of Murdoch's former editors and broadcast executives, Andrew Neil, said the allegations represented one of the"most significant media stories of modern times."
Neil, a former editor of the Sunday Times and chairman of Sky TV, said the story revealed that such levels of hacking were "systemic throughout the News of the World, and to a lesser extent the Sun."