Scott Morrison has called in the head of his department to investigate when the Prime Minister's Office (PMO) learned about the alleged rape of a now-former Liberal staffer.
Mr Morrison remains adamant his office first found out about the allegation last week, a claim former Liberal staffer Brittany Higgins rejects.
He has announced the head of his department, Phil Gaetjens, will investigate the matter and check phone records, after text messages emerged that purport to show his office was notified in 2019, weeks after the incident occurred.
It is the fourth investigation the Prime Minister has announced this week.
Ms Higgins alleges she was raped by a male colleague in the office of then-defence industry minister Linda Reynolds in March 2019.
The new investigation comes after a now-former federal government adviser told the ABC a senior member of the PMO was informed about the alleged rape weeks after it occurred.
Mr Morrison has maintained his office only learned that the incident involved an allegation of sexual assault last Friday.
Now Mr Gaetjens, a former chief of staff to Mr Morrison and the current head of the Department of Prime Minister and Cabinet, will investigate phone and other records held by PMO staff.
The move came after News Corp published a screenshot which it said showed text messages between Ms Higgins and a male Liberal staffer in April 2019, the month before the federal election.
The former adviser, who asked not to be named, told the ABC he called a member of the PMO in April 2019 to inform him of the alleged incident and seek more support for Ms Higgins.
He said he called the PMO with the support of Ms Higgins, and was particularly keen to escalate concerns about the delay in making counselling support available.
The ABC has also obtained a text message, first reported by The Australian, in which the former adviser told Ms Higgins he had spoken to the Prime Minister's Office.
"Spoke to PMO. He was mortified to hear about it and how things have been handled. He's going to discuss with [chief of staff] - no one else. I flagged need for councillor (sic) and desire to be closer to home during election."
Ms Higgins replied via text message, "Thank you for doing that".
The PMO staff member who received the call in April 2019 referred questions to Mr Morrison's media office. A spokesman for the Prime Minister confirmed a call took place, but denied any rape allegation was raised in the conversation.
On Friday, a senior government source insisted the rape allegation remained unknown to the PMO until last week, and said the matter was only being treated as a security breach before that.
The source said the conversation between the government adviser and the PMO was about finding Ms Higgins another job.
Opposition Leader Anthony Albanese said the text messages showed the Prime Minister's account was not credible.
"Well, it completely contradicts what the Prime Minister has said," Mr Albanese said.
"Here you have text messages clearly indicating that it was raised with the Prime Minister's Office, and the response from the Prime Minister's Office saying that he would raise it with the chief of staff."
Former prime ministers Kevin Rudd and Malcolm Turnbull have said it is not credible that a Prime Minister's Office would be unaware for years.
Earlier this week, Mr Morrison announced Stephanie Foster, a senior bureaucrat from the Department of Prime Minister and Cabinet, will investigate whether there is sufficient support for people who work in the Federal Parliament.
Liberal backbencher Celia Hammond, a former university vice-chancellor, will also investigate the workplace culture within the Liberal Party.
A bi-partisan, independent committee will also investigate the workplace culture and support available to staff but is likely to take months to begin its work.
After days of sustained pressure over how she handled the alleged rape, Senator Reynolds, now the Defence Minister, wiped away tears and was unable to answer questions in the Senate yesterday.
On Monday night, an extended interview with Ms Higgins was broadcast on Channel Ten's The Project.
She went through the details of the alleged rape in Ms Reynolds's office and how she was taken into a meeting a few days later in the same room.
"For my part, I am deeply sorry that Brittany felt unsupported at the time of the incident and in the months that followed," Senator Reynolds said on Thursday.
"I am also deeply sorry that some of my actions and handling of this matter added to Brittany's distress."
