Peter Saunders, who was hand-picked by the Pope six months ago to be the Catholic Church's commissioner for the protection of children, says Cardinal Pell's position in the church has become "untenable".

"The false and misleading claims made against His Eminence are outrageous. The Cardinal is left no alternative but to consult with his legal advisers," a statement issued on behalf of Cardinal Pell said.

Cardinal Pell has repeatedly denied claims he tried to bribe an abuse victim to keep quiet and he was dismissive of and dealt heartlessly with victims and their families.

Mr Saunders has told the Nine Network's 60 Minutes program that Cardinal Pell should be sent back to Australia and should fulfil a moral obligation to front the royal commission into child sexual abuse.

He said the position of the cardinal was untenable "because he now has a catalogue of denials".

"Given the position of George Pell as a cardinal of the church and a position of huge authority within the Vatican, I think he is a massive, massive thorn in the side of Pope Francis' papacy if he's allowed to remain."

The statement issued on behalf of Cardinal Pell said he had always taken a strong stand against child sex abuse and had put in place processes to ensure complaints could be brought forward and independently investigated.

"Cardinal Pell has never met Mr Saunders, who seems to have formed his strong opinions without ever having spoken to His Eminence," it said.

Cardinal Pell has promised full co-operation with the royal commission and has said he will attend hearings if asked to do so.