The sexual assault allegations made by Ms Higgins, and now three other women, are set to again dominate the parliamentary sitting week, with Prime Minister Scott Morrison avoiding a commitment to make public a report into who knew what and when in his office.

Four reviews have now been commissioned into various elements of the saga, and now more than 50 leading women and organisations have written to Mr Morrison, calling for a full review of Parliament as a workplace to be conducted by Sex Discrimination Commissioner Kate Jenkins.

The signatories include leading voices across the law, academia and business, such as Michele O'Neil from the ACTU, former presidents of the Law Council of Australia, and boss of the Australian Council of Social Service Cassandra Goldie.

The new allegation against the former staffer, made to the ABC, is that he reached under a table at Public Bar in Manuka in 2017, stroking the woman's thigh.

The latest woman to come forward has filed a report at a police station in Canberra and will make a formal statement later this week.

She came forward to the ABC after Brittany Higgins alleged she was raped by the man in 2019.

Two other women - a Liberal staffer, and a former party volunteer - have also alleged they were sexually assaulted by him. Ms Higgins is scheduled to make a statement to ACT Policing on Wednesday, asking for the investigation into her alleged assault to be re-opened.

While the government has committed to a range of reviews, the signatories of the letter say a full review by Ms Jenkins is needed.

"With the issues raised so squarely in Brittany Higgins' case, now is the time to examine, review, recommend and regulate what happens in Australia's most symbolic and important workplace," the letter, which was delivered to Parliament House on Monday morning, said.

"It is time for Australia's Sex Discrimination Commissioner to conduct a national review of Parliament as a safe and equal workplace."

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Speaking on ABC Radio on Monday morning, Finance Minister Simon Birmingham said he had already spoken with Ms Jenkins on the weekend as part of the independent review that would be commissioned by his department.

"As I work through this process of consultation with all of the different other parties and independents across the parliament to seek their input into the terms of reference into potential reviewers or reviewers who might be involved in the process," he said.

"I'll equally be trying to reach out to engage with different staff representatives and indeed some of those who have raised issues in the past to make sure that considerations just at the establishment of this review are thorough and comprehensive and taking into account all the different perspectives."

The letter, organised by Kim Rubenstein and Trish Bergin, leaders of the 50/50 by 2030 Foundation, commended Mr Morrison for the reviews announced so far, but said "in addition, we urge you and the Minister for Women and Attorney General to go further and launch a full review of Parliament as a safe and equal workplace".

"As the expression of the national will and Australia's most high-profile workplace, the Parliament is not just any workplace. If Parliament can get the culture right, it will set the standard and expectations across Australian workplaces," it said.

Ms Higgins was employed in Defence Minister Linda Reynolds at the time of the alleged incident, in March 2019. In Question Time on Monday Senator Reynolds refused to answer some questions, citing Ms Higgins' privacy.

The alleged rape has sparked several inquiries into workplace cultures in Parliament House and the coalition. A report to be prepared by Philip Gaetjens, Secretary of Prime Minister and Cabinet and former chief of staff to the Prime Minister, will look at who knew what and when in the Prime Minister's office. On Monday Mr Morrison avoided any commitment to making that report public.

Labor's upper house leader Penny Wong said Senator Reynolds had questions to answer about how the complaint by Ms Higgins was handled.

"She wasn't being treated as a human being. She wasn't being treated as a rape survivor and she wasn't being treated as a victim of a grave crime," she told parliament.

"She was being treated as a political problem."

Senator Wong said Prime Minister Scott Morrison's words rung hollow while there was no culture of accountability.

"We know that at best, Mr Morrison runs a government where the culture is don't ask, don't tell when it comes to serious criminal allegation," she said.

"At worst, Mr Morrison himself is part of the cover-up."

Senator Birmingham said all the incidents weighed heavily.

"That is why we have to - and must - change culture and practices," he told ABC radio.

"The type of work that the Prime Minister has asked me to do is to work across party lines with the Opposition, with the Greens, with staff and with experts to ascertain how we can best change the workplace."

Ms Higgins initially chose not to pursue a police complaint, fearing her job would be on the line.

Senator Birmingham said in circumstances where somebody chose not to proceed with a police complaint, there was a balance to be struck by those who were informed of the allegations.

He said respecting the rights of individuals to make decisions needed to be weighed against the responsibility of others to pursue action.

"Balancing those privacy considerations of the individual but the broader safety questions that that are clear and apparently raised," the minister said.

- with AAP