Former Liberal staffer Brittany Higgins will make a formal Police complaint on Wednesday, allowing the start of an active investigation into her alleged rape inside a ministerial office at Parliament House.

At the same, time her former employer, Linda Reynolds, will face a grilling at the National Press Club when she fronts media cameras for the first time since Ms Higgins made the bombshell allegation that she was sexually assaulted on the Defence Minister’s couch in 2019.

Three women have now come forward to accuse the same former Liberal staff colleague of rape, with a fourth claiming the man had stroked her thigh at a bar.

Ms Higgins has she did not proceed with a formal complaint after an initial meeting with police because she did not want to lose her job and felt unsupported.

In a statement she outlined her reasons for re-activating the police investigation, saying she wanted her alleged attacker to face the “full force of the law” and to ensure her ordeal is not repeated.

“I am determined to drive significant reform in the way the Australian Parliament handles issues of this nature and treats ministerial and parliamentary staff more generally,” Ms Higgins said.

“I believe that getting to the bottom of what happened to me and how the system failed me is critical to creating a new framework for political staff that ensures genuine cultural change and restores the trust of staff.”

The government has merged two of its four inquiries into the rape report and culture inside Parliament House, as Prime Minister Scott Morrison faces yet more questions over his knowledge of misconduct allegations against Liberal employees.

Liberal MP Celia Hammond, entrusted by the PM with responsibility to review Liberal Party standards and culture amid the mounting scandals, has recommended that her process be combined with a multi-party process spearheaded by Finance Minister Simon Birmingham.

Brittany Higgins. Photo: supplied

“She has recommended to me, together with Anne Webster from the Nationals, that that process be consolidated into this broader multi-party process,” Mr Morrison said at Parliament House on Tuesday.

Senator Birmingham has been consulting with Labor and crossbench MPs on the broader review, which will examine issues facing Parliamentary staff, such as cultural problems and how workplace complaints can be reported and responded to.

The PM has repeatedly declined to commit to making public a report into what his office knew about the incident involving Ms Higgins, and when.

Mr Morrison has asked Phil Gaetjens, his former chief of staff and now the secretary of the Department of Prime Minister and Cabinet, to investigate whether those inside the PM’s office knew about the rape allegations but did not pass on the message.

Scott Morrison feels the pressure. Photo: AAP

Major questions have been raised about why Mr Morrison did not, in his telling of the story, know about Ms Higgins’ allegations for nearly two years – despite the knowledge of several government ministers, the President and Speaker of the Parliament, and even staff inside his office.

Major questions for Reynolds

Senator Reynolds’ appearance at the National Press Club marks the first time she will face media questioning since Ms Higgins went public with her allegations.

The Minister has weathered days of intense questioning in the Senate from Opposition politicians, but will now face a dozen or more questions in a live and nationally televised appearance regarding what she knew about the alleged rape and what she did – or did not do – to respond.

Ms Higgins alleged the incident occurred while working for Ms Reynolds. Photo: AAP

Senator Reynolds broke down in the Senate last week, following intense questioning from Labor on her response to Ms Higgins’ complaint.

She had been scheduled to address the Press Club for some weeks, before Ms Higgins’ allegations surfaced.

More pressure on Morrison

Controversial MP Craig Kelly has been unwittingly drawn into the conversation about culture in Parliament, with his defection from the government – according to Coalition sources – partly linked to his refusal to sack a long-time staffer who is subject to an apprehended violence order.

A young female co-worker had accused the man, Frank Zumbo, of inappropriate conduct in the office.

Mr Kelly denied his resignation from the Liberal Party was linked to his support for Mr Zumbo, saying the man was “entitled to natural justice and the presumption of innocence” and “there are no criminal charges against him”.

Mr Morrison said he had asked Mr Kelly to end the man’s employment, and that Mr Kelly had failed to “take some certain actions”.

The Department of Finance, which handles work-related complaints from ministerial staff, is now looking into issues raised against Mr Kelly’s staffer.

In Question Time on Tuesday, Opposition Leader Anthony Albanese asked, “Why did the Prime Minister do nothing for years?”

Mr Morrison responded he had only become aware of the inappropriate allegations “over the last few weeks”, but had raised separate “performance issues” around Mr Zumbo previously.

• For confidential help and support surrounding sexual assault, contact 1800 RESPECT online or by calling 1800 737 732