Attorney-General Christian Porter has identified himself as the minister accused of historical rape but declared categorically that the 1988 claimed assault “simply did not happen”.

A highly emotional Porter told a Perth press conference he had not slept with the then 16-year-old who made the allegation more than three decades later. “We didn’t have anything of that nature happen between us,” he said.

Porter declared he was not standing down from his position as first law officer.

“If I stand down from my position as Attorney-General because of an allegation about something that simply did not happen, then any person in Australia can lose their career, their job, their life’s work based on nothing more than an accusation that appears in print.

"If I were to resign and that set a new standard, there wouldn’t be much need for an attorney-general anyway because there would be no rule of law left to protect in this country.”

Porter will take a couple of weeks leave to “assess and hopefully improve my own mental health”.

“I think I will be able to return from that and do my job.”

He said he has been asked by colleagues “Are you OK?”. His answer was “I really don’t know. I am not ashamed to say it - I am going to seek some professional assessment and assistance on answering that question over the next few weeks.”

Porter said that in the past few days, while he had remained silent during the legal process, he had been subject to “the most wild, intense and unrestrained series of accusations I can remember in modern Australian politics.”

He said he had never had the allegation put to him in any substantive form before last Friday’s publication. “No-one put anything in any detail to me seeking a response.” He had never seen the woman’s statement, although a statement from her was included with the letter sent to Prime Minister Scott Morrison last week. The ABC published the allegation late Friday.

On the incident itself, Porter said when he was 17 and she was 16 they were both on the Australian schools debating team for a competition in Sydney. He remembered her as an “intelligent, bright, happy, person.”

He was noticeably reluctant to go into detail. Under questioning, he said he did not think he had ever been alone with her, but admitted “it’s not impossible,” while saying he was never in her room.

He recalled a memory, sparked by what he had read of the material - “I don’t think any of us had ever ironed a shirt before, and I recall, she showed us how to do that, I remember that.”

It was a team of four, including three boys and “we did what normal teenagers would do”.

“I remember two evenings that week. One was a night at one of the colleges with bowls of prawns, which sticks in my mind. I do remember a formal dinner and going out dancing sounds about right.”

He said he was not in contact with the woman - who took her own life last year - in subsequent decades.

Porter began his news conference by referring to the woman’s parents, saying he hoped they would understand that in denying the allegation “I do not mean to impose anything more upon your grief”.

He rejected the volley of calls into an independent inquiry into the allegation.

“What would that inquiry ask me to do? To disprove something that didn’t happen 33 years ago.”

“I honestly don’t know what I would say to that inquiry. Of course I can’t.”

Porter said he had spoken to Scott Morrison and had his full backing.

He said he was deeply sorry for the fallout the issue has had for his colleagues.

“My colleagues have become the target of allegations and speculation themselves. My colleagues are my friends. And I’m deeply sorry to each of them for that.”

The issue exploded last week when friends of the woman wrote to Morrison and several other parliamentarians demanding an inquiry into her allegation. The letter included a statement the woman had made, detailing her alleged experience.

The woman went to the police a year ago but had not made a formal complaint.

The allegation has derailed the government for a week, when it was already struggling to contain the fallout from former staffer Brittany Higgins’ allegation she was raped by a colleague in the office of the then Defence Industry Minister Linda Reynolds in 2019.

On Monday, Morrison said the woman’s allegation against Porter was a matter for the police. The federal police referred it to the NSW police. The NSW police said on Tuesday that, “based on information provided to NSW Police, there is insufficient admissible evidence to proceed.

"As such, NSW Police Force has determined the matter is now closed.”

Porter denied the allegation to Morrison on Wednesday of last week.

The ABC’s Four Corners was pursuing the woman’s story last year, but in the end was not in a position to include it in its November program “Inside the Canberra Bubble”. That program reported sexist comments made by Porter as a young man.

Porter entered federal parliament in 2013 after a high profile career in Western Australian politics, where he served as attorney-general and treasurer.

Federally, he was social services minister in 2015-2017, before becoming attorney-general. After the 2019 election, industrial relations was added to his responsibilities.

Australian of the Year Grace Tame, an advocate for victims of sexual abuse, answering questions at the National Press Club, criticised Morrison over invoking his wife Jenny’s counsel that he should think of the Higgins’ situation as a father. “It shouldn’t take having children to have a conscience,” Tame said.

Michaelia Cash will be acting attorney-general while Porter is on leave.