As the government was forced to further justify its response to the allegation by former staffer Brittany Higgins that she was raped in a ministerial office two years ago, and felt pressured to cover up the assault for the good of the party, it can be revealed yet another attempt to protect parliamentary staff was rejected last year without negotiation.

The union representing staffers in ministerial and parliamentary offices has been negotiating a new agreement with the Department of Finance since last year, but a proposed clause covering gendered violence and sexual harassment was rejected by the government without discussion in the opening stages of negotiations.

According to the proposal, seen by The Canberra Times, the government would have had to recognise "unique risks and hazards exist in the employment of Member of Parliament Staff (MoPS) including but not limited to the asymmetrical power structures of the workplace and obstacles that exist in reporting incidents".

It also would have created an obligation for the government to "provide a working environment that is safe" and "take all reasonable steps to remove sexual harassment, gendered violence, third party violence, bullying from the workplace".

Community and Public Sector Union national secretary Melissa Donnelly wrote to Prime Minister Scott Morrison on Tuesday, calling for the particular risks in the working relationship with staffers to be addressed.

Prime Minister Scott Morrison wrote to Labor leader Anthony Albanese late on Wednesday, as well as to minor party leaders and crossbenchers, committing to working "in a bipartisan way" to develop an independent review into workplace conditions for staffers in Parliament House.

Finance Minister Simon Birmingham would be responsible for developing the review, in his role as Special Minister of State. Senator Birmingham also leads the department that rejected the clause the union wanted to protect staffers from harassment, violence and bullying.

Senator Birmingham did not say why the government rejected the proposed clause, but left the door open for it to be reconsidered.

"Bargaining for a new agreement will resume later this week and the government is committed to hearing and discussing key issues from all bargaining representatives," he said.

In a new statement released on Wednesday, Ms Higgins criticised the Prime Minister's "victim-blaming rhetoric" over the incident, saying it was distressing to her and other survivors.

Ms Higgins went public with her story this week, which she says has resulted in her finding out key elements of what happened.

That includes finding out security guards had let her and the alleged perpetrator into Parliament House.

"I didn't know that security guards came into the office multiple times seeing me in a state of undress," Ms Higgins said.

"I didn't know they were undertaking an internal review into how the matter was handled at the time. I didn't know that they debated calling an ambulance at the time of the incident.

"The continued victim-blaming rhetoric by the Prime Minister is personally very distressing to me and countless other survivors."

Ms Higgins said she had been denied access to CCTV footage of her from that evening by a senior staffer to Mr Morrison and her former chief-of-staff.

"And (they) continually made me feel as if my ongoing employment would be jeopardised if I proceeded any further with the matter," she said.

"The government has questions to answer for their own conduct."

Mr Morrison remains under intense scrutiny over what he knew about the incident.

The Prime Minister says his office only found out about the allegations last week and he was not aware until Monday.

The rejected proposal for the employment agreement is part of a long list of missed opportunities for the government to address the historic and deep-seated issues in parliamentary offices, including rejected bills from the crossbench and the Greens for standards or codes of conduct to be implemented for MPs.

Department of Finance secretary Rosemary Huxtable committed to review the policies relevant to the employment of staffers last year in the wake of the ABC report alleging a culture of sexism within ministerial offices. It is unclear what progress has been made on that review.

Independent MP Helen Haines was among the crossbench MPs calling for an independent, external review of how workplace grievances and complaints are dealt with in Parliament House, that would look at changes to the Members of Parliament (Staff) Act and the formation of an independent body that would look at future complaints and grievances.

In October last year Dr Haines introduced a bill for a parliamentary standards commissioner, alongside a bill for a federal integrity commission, which would put in place standards for MPs and senators, and a commissioner to advise and hold MPs to account.

As calls grow across the political spectrum for an independent body to hear such complaints, Dr Haines said her bill is among many existing suggestions to fill the gap.

"There's a bill before the parliament right now that may be a remedy we could look to," she said.

"We've got a structural problem, it should be straightforward - that's there's a code of behaviour, a set of standards, a process, and there's no process for complaints here."

READ MORE:

Dr Haines said it was distressing and frustrating to hear Ms Higgins' story of alleged rape and the lack of support that was offered to her in the aftermath.

"How many of these allegations does it take before we do something about this?"

Question time in both the House and the Senate again revolved around who knew what and when within the government, leading to fiery exchanges between the major parties. But Dr Haines said the response to Ms Higgins' allegation must not be politicised.

"If we have a workplace whereby complaints can't be made because they are politicised, that's a terrible thing," she said.

The former head of the Office for Women, Trish Bergin, said it was "anachronistic" that parliamentary offices had resisted scrutiny of employment practices for so long.

"It's so out of step with where the corporates are, in terms of really cracking down on these things," Ms Bergin, who now heads up the 50/50 by 2030 Foundation at the University of Canberra, said.

Current provisions have "very weak controls and support for individuals", Ms Bergin said.

"I believe that Linda Reynolds followed the letter of the law of the existing code of conduct in addressing Brittany's complaint, and it still left her feeling completely unsupported."