Attorney General Dominic Grieve is looking into concerns that policewoman Sue Akers, who is leading the investigation into illegal newsgathering, could have prejudiced any potential trials.
Grieve's office is examining the testimony given to the Leveson inquiry by the policewoman after receiving at least one complaint.
The Scotland Yard Deputy Assistant Commissioner is in charge of three linked inquiries into phone hacking, illicit payments and computer hacking.
She told the inquiry that the Sun newspaper had a "network of corrupted officials" across bodies such as the police and Ministry of Defence.
One individual had received £80,000, while one journalist made payments to sources totalling more than £150,000 over a period of years, she said.
A spokeswoman for the Attorney General said: "Evidence given during the Leveson inquiry has been drawn to the attention of the Attorney General's office.
"The Attorney General will consider the concerns raised."
Meanwhile, the hearing will today hear from former Scotland Yard commissioner Lord Blair, who was forced to resign as head of the Metropolitan Police in October 2008 after London Mayor Boris Johnson made it clear he wanted him out.
He is expected to be asked what he knew about the decision to restrict his force's 2006 investigation into phone-hacking at the News of the World.
Lord Blair is also likely to describe his often strained relations with the media.
He said in a statement to the Leveson Inquiry: "I believe that where the problem may have become significant is that a very small number of relatively senior officers increasingly became too close to journalists.
"Not, I believe, for financial gain, but for the enhancement of their reputation and for the sheer enjoyment of being in a position to share and divulge confidences.
"It is a siren song. I also believe that they based their behaviour on how they saw politicians behave, and that they lost sight of their professional obligations."
The inquiry will also hear today from former Met assistant commissioner Bob Quick, who resigned in 2009 after accidentally displaying details of a secret operation to photographers as he entered Downing Street.
Further testimony will come from ex-Scotland Yard deputy commissioner Tim Godwin, who left the Met in January after temporarily serving as acting commissioner when Sir Paul Stephenson quit over the phone-hacking scandal last July.
The Met's original phone-hacking inquiry resulted in the jailing of News of the World royal editor Clive Goodman and private investigator Glenn Mulcaire in January 2007 after they admitted intercepting voicemail messages left on royal aides' phones.
However the force was widely criticised for limiting the scope of the investigation despite evidence from Mulcaire's notebooks that there could be many more hacking victims.
Prime Minister David Cameron set up the Leveson Inquiry last July in response to disclosures that the News of the World hacked murdered schoolgirl Milly Dowler's phone after she disappeared in 2002.
The first part of the inquiry, sitting at the Royal Courts of Justice in London, is looking at the culture, practices and ethics of the press in general and is due to produce a report later this year.
The second part, examining the extent of unlawful activities by journalists, will not begin until detectives have completed their investigation into alleged phone-hacking and corrupt payments to police, and any prosecutions have been concluded.
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