Former attorney general Lord Goldsmith has denied claims that he overlooked widespread allegations of phone hacking in 2006 in favour of a "much narrower" investigation.
Conservative MP Geoffrey Cox told the House of Commons the Labour peer had been informed that a "vast array of numbers had been tapped" by private investigators at News International.
He said Lord Goldsmith gave his approval for the police inquiry to focus on News of the World royal reporter Clive Goodman and private detective Glenn Mulcaire, who were later convicted.
Lord Goldsmith told BBC2's Newsnight: "I wasn't told about any of the other allegations. As background in the briefing that I had about those cases (Mulcaire and Goodman), I was told that the police believed there were other cases as well. But they were talked about in terms of there being probably further investigations in due course.
"And I think the point to make absolutely plain was that there was never any request to me, still less was there any answer from me, suggesting that the inquiry should be kept narrow. I'm not the Metropolitan Police Commissioner and I'm not the Director of Public Prosecutions (DPP). I superintend, which is general oversight."
He added: "As to why this wider investigation that was referred to didn't take place, you'll have to ask the police or the DPP Ken Macdonald what they did afterwards. It wasn't my responsibility - they didn't ask me for any advice, I didn't give them any advice, that's not what attorney generals do."
Mr Cox made his comments on Thursday during a debate on public confidence in the media and police.
He asked Home Affairs Committee chairman Keith Vaz: "Did you find as part of your investigation that the Attorney General had been informed in 2006 - on 30 May, to be precise - that a vast array of numbers had been tapped by investigators employed by News International?
"The then attorney general's approval was sought for a much narrower focused investigation, which plainly, by implication, was given. Is it not clear that ministers knew in 2006 that there was a great array of tapped phone numbers that could have given rise to a wider investigation, but they never allowed the police, or instructed the police to carry it out?"
Mr Vaz, a Labour MP, replied: "No witness who came before the committee has said that to us."