Former Conservative MP Louise Mensch, who was a member of the parliamentary committee investigating phone hacking, said journalists told her that the practice was "widespread" within the industry.
Ms Mensch said: "I remember during the parliamentary inquiry into hacking, I was very clear, journalists were coming to me all the time saying this was a widespread practice in Fleet Street, and the further we get into it the more true that becomes."
Earlier, it was revealed that former Daily Mirror editor Piers Morgan was questioned under caution last December about phone hacking but was not arrested.
Piers Morgan has confirmed he was questioned by police about phone hacking at the Mirror newspaper group - although it is not the first he has been linked to the hacking scandal.
In his memoirs, published in 2003, the former Daily Mirror editor appeared to suggest he knew all about phone hacking, and he then repeated those stories to the media when he gave interviews.
Then he appeared before Lord Leveson at his inquiry in late 2012, and said that absolutely no hacking took place under his editorship at the Daily Mirror, going back on all those earlier suggestions.
Morgan is now based in the US, but flew back to the UK in December to be questioned by police, after being approached by officers belonging to Operation Golding which was set up to look into voice message interception.
The Mirror Group deny that any kind of hacking occurred at their newspaper group.
Former Daily Mirror editor Piers Morgan has been questioned under caution about phone hacking, Press Association sources have confirmed.
"A 48-year-old man, a journalist, was interviewed under caution on 6 December 2013 by officers from Operation Golding in connection with suspected conspiracy to intercept telephone voicemails," a Metropolitan Police spokesman told ITV News.
"He was interviewed by appointment at a south London police station. He was not arrested."