Murdoch told the Leveson Inquiry in a witness statement "evidence of alleged or suspected illegality" by News International staff was being sent to the U.S. Justice Department, the Telegraph reported.
He said the company's Management and Standards Practice Committee has been cooperating with the Justice Department since last July.
"This company has been my life's work," Murdoch said, "and I feel a strong sense of responsibility for everything we do and fail to do."
Murdoch denied being one of the main powers behind former Prime Minister Margaret Thatcher during questioning about the relationship between politicians and the media, the Telegraph reported.
He told the inquiry he "never lets commercial considerations" enter into decisions about which political parties his papers back in general elections.
Murdoch drew laughter from the audience when he admitted telling former Prime Minister Tony Blair, "If our flirtation is ever consummated Tony, I suspect we will end up making love like porcupines: very, very carefully."
In earlier testimony, James Murdoch, the U.S. multinational media giant's deputy chief operating officer, said he had a "tiny side conversation" with Prime Minister David Cameron Dec. 23, 2010, about the Murdoch conglomerate's interest in winning government approval for a $12 billion takeover of British Sky Broadcasting Group PLC, the younger Murdoch testified.
The conversation took place at a Christmas dinner at the home of then-Murdoch British newspaper executive Rebekah Brooks, with whose husband Cameron is close friends, the younger Murdoch told the judge-led inquiry into British media practices.
Brooks resigned last summer at the height of a scandal involving phone hacking by Murdoch tabloids. She is one of 46 people arrested in an investigation into Murdoch-tabloid wrongdoing.
Cameron's office previously insisted the prime minister had "not been involved" in discussions about the bid and initially denied the Christmas encounter had taken place.
Cameron was to appear before Parliament Wednesday and is expected to appear before the media-practices inquiry, led by Judge Brian Leveson, at a later date.