More than 300 politicians and staffers have already come forward to a Human Rights Commission inquiry into workplace culture inside federal politics, but the nation’s sex discrimination commissioner wants more people to speak up.

“With such widespread commitment and action, I hope history will record 2021 as the turning point in eradicating sexual harassment in our workplaces,” Kate Jenkins told a Senate hearing on Monday.

One of several parliamentary probes set up after multiple sexual assault and harassment allegations in the political sphere, the Australian Human Rights Commission’s ‘Independent Review into Commonwealth Parliamentary Workplaces’ handed down its interim report on Monday.

Following a cross-Parliament agreement, Ms Jenkins had been tasked with investigating “the culture of Commonwealth parliamentary workplaces”.

The review was asked to ensure federal political workplaces maintained “best practice in the prevention of, and response to, incidents of bullying, sexual harassment and sexual assault”.

Harassment and bullying inside Parliament House is in the spotlight. Photo: AAP

The full report is due in November, but Ms Jenkins’ progress report revealed at least 345 people had already come forward – including 256 people who had worked for MPs or senators, 54 who worked in other parliamentary settings, and a handful of volunteers and interns.

In stark contrast, only 16 current or former politicians have so far engaged with the process.

There are 227 MPs and Senators in the current federal Parliament.

• Related: Parliament staff demand urgent workplace changes to fix ‘toxic culture’

Speaking to the ABC on Monday, Ms Jenkins said the politicians who had participated had been “really open and honest”.

She said their “very busy workload” helped account for the low number of MPs who had reached out to her.

Some 72 per cent of those involved with the process were women, while 28 per cent were men.

“Your commitment and drive to positive cultural change is clear,” Ms Jenkins said in a social media video, addressing those who had already come forward.

“The message that keeps coming through in submission after submission … is that workers in parliamentary workplaces, at every level, want positive change.”

Tweet from @AusHumanRights

The review will soon distribute an online survey to current staff and politicians asking about the “current prevalence and nature of bullying, sexual harassment and sexual assault in Commonwealth parliamentary workplaces”.

In-person focus groups will also soon be held around the country.

The commission has conducted 222 interviews and booked a further 125.

“We want to get a broad sense of the culture of parliamentary workplaces, including electorate offices, and what it’s like to work in them,” Ms Jenkins said.

“We want to know what is working well, so if you’ve had a positive experience, we want to hear from you too.”

Previously, Parliament staff had been cautious about working with the inquiry, fearing their reports may not remain anonymous.

The Parliament later made changes to guarantee people’s privacy would be protected.

In an opinion piece for the Sydney Morning Herald, Ms Jenkins admitted she had been “nervous” about what response the inquiry would receive.

She praised the “courage” of those who had made submissions and called the review “a once-in-a generation opportunity for change”.

Finance Minister Simon Birmingham. Photo: AAP

Finance Minister Simon Birmingham, whose department has responsibility for the internal employment of political staff, urged those eligible to engage with the process.

“This review will play a critical role in ensuring that the Parliament of Australia applies the cultural and practical changes necessary to set a positive example for the nation,” he said in a statement.

“I continue to encourage all those who choose to do so, to share their experiences, as this will be vital to informing the review and helping to ensure a safe and respectful workplace.”

Also on Monday, Ms Jenkins appeared before a Senate committee hearing into the Sex Discrimination and Fair Work bill, launched off the back of her landmark Respect@Work report.

That report, published last year, made 55 recommendations but the federal government has been criticised for not acting sooner.

Ms Jenkins told the Senate that federal Parliament should legislate a ‘positive duty’ for employers to stamp out sexual harassment and discrimination in the workplace, not just respond when allegations are made.

“It is shocking to realise that the only law that currently explicitly prohibits sexual harassment – the Sexual Discrimination Act – contains no obligation for employers to prevent sexual harassment,” she said.

Julia Fox, assistant national secretary at retail workers’ union the SDA, said employees had been forced to wear clothing with “I’m free” and other inappropriate slogans.

Kate Jenkins appears before the Senate hearing via video link. Photo: AAP

“The employer at the time didn’t put the two and two together, but the overwhelming response to workers at that time was unbelievable levels of sexual harassment occurred,” she said.

“We’ve had other employers in the past that required employees to wear T-shirts and badges that say ‘I love sex’.”

Business groups including the Australian Chamber of Commerce and Industry and the Australian Industry Group have resisted calls for employers to be legally obliged to prevent harassment.

They argue sexual harassment is banned under existing rules and fear duplication could lead employers to be exposed to multiple penalties for the same incident.

Ms Jenkins also wants the Fair Work Commission to be given powers to issue a stop sexual harassment order and make it easier for victims to pursue civil cases.

Home Affairs Minister Karen Andrews urged all federal politicians to undertake the optional sexual harassment training to be offered in Parliament.

“I would be encouraging every single politician in this building to make sure that they at least attend that hour of training,” she said on ABC radio.

“I’ll be making sure that I’m attending. They should go out and do that. And that’ll be a pretty clear demonstration of their commitment and they should be held to that.”