Mark Lewis, who was instrumental in exposing the scale of criminality at Murdoch's News of the World, is said to be in the "advanced stages" of bringing a case against News Corp in the US.
The news comes as Murdoch is preparing to fly to London to deal with the latest fall out at publisher News International following a series of arrests of senior Sun journalists at the weekend.
According to The Independent, sources close to Lewis's legal team have scheduled "key meetings" in New York for the next few weeks.
An FBI investigation has so far found limited evidence to suggest that News of the World journalists attempted to illegally access the voicemails of 9/11 victims and their families. However, the bureau is thought to have instead focused on alleged bribery and illegal payments made by News Corp staff.
Should a case be brought against News Corp, the company's board - including Murdoch and his son James - would be potentially liable under US law if it was proved that they authorised the alleged bribes, or failed to prevent the crimes from happening.
News Corp has recently gone to great expense hiring a new legal team, including a former US justice department counsel, which suggests that the firm is preparing for a significant legal battle.
Following the latest arrests at The Sun, Murdoch has decided to fly to the UK for what one News Corp executive described as "five-star crisis management", with the very future of the tabloid under consideration.
News International chief executive Tom Mockridge sent an email to staff over the weekend stressing that News Corp had "empowered" an independent body, the management and standards committee (MSC) to co-operate fully with the police investigations into phone hacking, computer hacking and payments to officials.
But many Sun journalists are becoming increasingly concerned that the arrests, made after information was voluntarily handed over to police by the MSC, were part of a strategy to clean house and protect News Corp's global brand.
The Sun editor Dominic Mohan has said that he was "committed to leading the paper through this difficult period". But The Independent says that he has privately confided to colleagues that he cannot rule out also being arrested by the Met police's Operation Elveden team investigating corruption.
An NI journalist, who asked not to be identified, said: "Far from Dominic offering guarantees about leading the paper, he's told some of us he thinks he'll get his collar felt.
"He said his email traffic was 'colossal' because a lot of people preferred not to knock on his door in the climate. So he may have missed stuff that will be seen as dodgy."
Today, The Sun's associate editor Trevor Kavanagh said that the journalists were being "treated like members of an organised crime gang", and hit out at the "witch hunt" against the paper.