Malcolm Turnbull has demanded Bill Shorten state his knowledge of an investigation into embattled Labor MP Emma Husar, attacking the opposition leader's credibility.
However, the Labor leader has hit back saying the prime minister has questions to answer over one of his senior ministers.
The details of a NSW Labor investigation into bullying and harassment into Ms Husar's office were published by BuzzFeed News on Thursday.
It includes claims she flashed Labor frontbencher Jason Clare, sexual harassment and diversion of Labor funds into her personal bank account.
The allegations also include bullying, aggressive behaviour and using taxpayer money to hire a nanny who couldn't work a computer.
Mr Turnbull said the leak showed divisions in Labor, as he labelled the claims against Ms Husar as "very, very serious".
"It shows there's enormous enmity, there's like a civil war going on in the New South Wales Labor Party," Mr Turnbull said.
The prime minister called on Mr Shorten to outline what he knew about the investigation and when he was aware of it.
"His claim that this has all come as a surprise to him is simply not credible," Mr Turnbull said.
A spokeswoman for Mr Shorten said the Labor leader had only been informed of the investigation on July 18.
Mr Turnbull needed to come clean on whether Jobs Minister Michaelia Cash was being investigated by the federal police over a media tip-off about raids on union offices, the spokeswoman said.
Senior Labor frontbencher Anthony Albanese said he found it extraordinary that rumours and unfounded allegations were getting so much media coverage.
"The idea that you should have a running commentary while there is an independent investigation taking place is not fair, either to Emma Husar or to the people who have made complaints about her," Mr Albanese said.
Ms Husar said claims she sexually harassed staff and flashed another federal MP are "absolute lies" aimed at ruining her career.
Mr Clare said the allegation the western Sydney MP flashed him three times in his office was "categorically untrue".
"This smear is completely and utterly untrue, unfair and hurtful beyond belief. 100 per cent false," Ms Husar tweeted.
Ms Husar has publicly named and accused a former staffer and his father of fabrication, saying they would stop at nothing to destroy her.
"These are absolute lies that have been fabricated by [the ex-staffer], who's working with his father to leak against me and ruin my reputation," she said on Twitter.
NSW Labor said continued public speculation about lawyer John Whelan's investigation was a significant concern and was causing some delay to the inquiry.
Mr Whelan could provide a briefing about the investigation as early as next week.
Federal parliament resumes on August 13 after the winter break.