Former journalists at the Daily Mirror and Sunday Mirror reportedly said illegal hacking of voicemails was widespread at their papers. However, the claims were strongly denounced by their proprietors.
Rupert Murdoch shut down the News of the World on July 7, Britain's biggest selling Sunday newspaper due to the phone-hacking scandal.
James Hipwell, a former Daily Mirror financial journalist, said he was aware of hacking because he worked next to the showbusiness desk where it was rife.
"They would call a celebrity with one phone and when it was answered they would then hang up. By that stage the other phone would be into their (the celebrity's) voicemail and they would key in the code," said Hipwell, the AFP reported.
Piers Morgan, a former News of the World editor, now a presenter for US television news network CNN, has denied having any knowledge that phone hacking went on under his editorship.
An unidentified former Sunday Mirror journalist claimed to have witnessed routine phone hacking in the newsroom.
Trinity Mirror, the group which publishes both papers, said its journalists work within the law and the code of conduct of Britain's self-regulatory Press Complaints Commission.
On Thursday it emerged that police had requested files from a British data protection regulator which published a report showing the non-Murdoch Daily Mail, the Mirror and the Trinity Mirror-published The People were the biggest users of private investigators to seek confidential information, said the AFP.
