SYDNEY (BLOOMBERG, REUTERS) - Alarm about the workplace culture at Australia's Parliament heightened on Saturday (Feb 20) amid claims that a former government adviser accused of raping a junior female colleague in the building had sexually assaulted another woman.

Prime Minister Scott Morrison said he was extremely distressed by a report of the alleged assault on the second woman, adding that a lot of work had to be done to change the workplace culture.

"I think we've got a problem in the Parliament and the workplace culture that exists there," Mr Morrison told reporters in Sydney on Saturday.

"We would be naive to think it's not a challenge that other workplaces face all around the country, but I agree the Parliament should be setting the standard."

Mr Morrison welcomed a decision by the first woman, former adviser Brittany Higgins, to now make a formal complaint with the Australian Federal Police about her alleged rape in the building in 2019.

The case involving the second woman, a former staffer in Mr Morrison's Liberal Party, was not in Parliament House, according to The Australian newspaper.

The second woman alleged she was sexually assaulted by the man in 2020, after he had been sacked following Ms Higgins's allegations and while he was working in the private sector.

The second alleged attack occurred at the woman's home after the two had been out for dinner, she was quoted as saying.

A police media liaison officer in the capital Canberra said on Saturday there was an "open" investigation into the incident involving Ms Higgins but that the case was not "active" because she had not filed a formal complaint.

The accusation by the second woman had not been referred to police, the liaison officer said.

Ms Higgins told the ABC this week she had not been encouraged to make a police complaint at the time of her assault when she worked in parliament for Defence Minister Lynda Reynolds.

Ms Reynolds says Ms Higgins was not pressured against making an official complaint.

Ms Higgins' allegations came after former lawmakers from the Liberal Party complained about workplace bullying in Parliament.

In 2018, former foreign minister Julie Bishop blasted behaviour in Parliament that wouldn't be "tolerated in any other workplaces across Australia", while former lawmaker Julia Banks said bullying had driven her to decide to quit the legislative body.