Detectives investigating the phone hacking scandal are examining fresh claims after new evidence came to light, a lawyer representing victims said on Saturday.
Scotland Yard contacted senior lawyers representing victims to say the new allegations relate to the now defunct News of the World's feature desk and Trinity Mirror titles.
Victims' lawyer Mark Stephens, who represented murdered schoolgirl Sarah Payne's mother Sara, said the group was informed of the new developments two weeks ago.
Stephens said he could not confirm reports that an estimated 600 fresh allegations have emerged, or that they have come from a whistleblower being lined up as a crown witness.
Fresh legal actions are now expected to come from new victims and litigants who have already settled with News of the World publisher News International, but signed agreements allowing them to sue again.
Sara Payne's lawyer has said that some 600 new claims have emerged
Stephens said: "We have been told a significant amount of information has just come to light which the police have not yet had time to go through.
"They are doing so methodically and carefully. But until they have finished analysing it, it is very difficult to say how it will come out."
Police were originally expected to conclude their Operation Weeting investigation into the phone hacking scandal by the end of this year.
But Stephens said that they are now looking at a 2015 end date, with a 2016 conclusion "more likely".
The revelation comes after four current and former Trinity Mirror journalists were arrested in early morning raids on Thursday.
The claims are some of the first not to originate from News International's News of the World
People editor James Scott and deputy editor Nick Buckley were held, along with former editor of the Sunday Mirror Tina Weaver and former deputy editor of the newspaper Mark Thomas.
They were all released on bail until April.
Former editor of the Daily Mirror, Richard Wallace, was also interviewed by police on Friday.
Scotland Yard said the alleged conspiracy is being treated separately from the two plots being investigated at the News of the World, and its inquiry is focused on the Sunday Mirror in 2003 and 2004.
On Monday, the High Court is expected to hear a case management conference in damages actions brought over the scandal last autumn.