Mr Murdoch's and Mr Gingrich's spokesmen gave differing reports on what day and month the meeting occurred. Critics of the speaker suggest the arrangement creates a possible conflict of interest.
Mr Gingrich's spokesman Tony Blankley said Mr Gingrich met the Australian-born media tycoon for about 10 minutes on 28 December. He said: "They passed the time of day, it was a 10-minute courtesy call." However, a publicist for Mr Murdoch said they met on 28 November, before the book deal became public, when Mr Murdoch was in Washington to call on officials, including Democrats.
But House Democratic whip David Bonior told a news conference that an outside counsel, a special non-House investigator, should be named to probe "Newt Gingrich's ethical problems" in light of the meeting.