Executive offers to front Porter inquiry

But the prime minister continues to insist there is no reason under the "rule of law" for Mr Porter to face any further action.

The ex-boyfriend of a woman who accused Mr Porter of raping her when they were both teenagers in 1988 said on Friday he had "relevant discussions" with Mr Porter over a number of years.

James Hooke, who is now senior managing director with Macquarie Group, has offered to appear before an independent inquiry.

Mr Porter, who is on mental health leave, has firmly denied the historical rape allegation and does not recall having discussed it with anyone.

Mr Hooke said he was concerned for Mr Porter's wellbeing and was devastated by the untimely death of his very dear friend.

"Mine is just one set of recollections, and I am aware of the fallibility of human memory, however unintentional," he said.

"That said, I have what I consider to be clear recollections of relevant discussions I had with her over the years from mid-1988 until her death.

"I also have what I consider to be clear recollections of relevant discussions I had with Christian Porter from April 1992 in Perth and through the mid-1990s."

Mr Hooke said he made himself known to NSW police last year after the woman's death and understood why they were unable to interview him.

"In relation to any criminal prosecution, Christian Porter was manifestly and appropriately entitled to the presumption of innocence - it is essential to the rule of law," he said.

"In relation to any investigation of the important non-criminal aspects of this matter, I support an inquiry, like either that conducted by three retired eminent judges after Justice Lionel Murphy was acquitted of charges or that conducted by Dr Vivienne Thom into allegations about Justice Heydon.

"I am willing to testify under oath at any appropriately convened inquiry."

The NSW Bar Association on Friday moved to clarify the use of the term "rule of law", saying it applied not only to criminal and civil matters but "executive inquiries" with "specific terms of reference setting out the scope of the inquiry".

"Each of these criminal and civil processes involves the ordinary and lawful use of state authority, and comprises an aspect of the rule of law."

The statement came as NSW police commissioner Mick Fuller told a state estimates hearing the woman made five primary contacts with police via email and phone before she took her own life last year.

But the woman never lodged a formal statement of complaint that could be admissible in court.

Mr Fuller had a "high-level discussion" about it with deputy commissioner David Hudson.

But asked whether he kept politicians including Mr Morrison informed of the matter, Mr Fuller said: "At no point in time in this matter have I had any communication with any member of government, federally or from a state perspective."

Mr Fuller said it was police custom and practice if a victim withdrew the matter "then, outside the victim care aspect of it is, the matter is finalised".

"And that is not (just) for the attorney-general, that is for every matter," he said.

"Now whether that is right or wrong, they are certainly things that we are looking at the moment with a whole broader range of things around the journey for victims into the justice system, particularly around sexual assault and historic sexual assault matters."

Mr Fuller said the last contact between investigators and the woman involved her saying she no longer wanted to proceed in the matter.

He said such a withdrawal was not unusual for victims, and it took enormous courage for people to come forward.

The police chief was aware the woman had prepared another document - which he described as a "diary entry" - and friends had passed it on to the AFP.

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Australian Associated Press