Malcolm Turnbull has renewed his attacks on Bill Shorten over the opposition leader’s assertion he was unaware of the allegations surrounding Emma Husar as “simply not credible”.

Those within the party have admitted her political future is limited and internal Labor conversations have centred on how best to handle the fallout of the claims and investigation, which is believed to be in its final stages. Members of Labor’s right faction have conceded Husar will most likely not contest the next election.

“It’s too public, it’s too much of a hangover,” one factional powerbroker said. “That horse has already bolted.”

So far, Shorten has avoided giving an opinion on Husar’s future, only saying he believed there was more to the story, and asking for space while the internal investigation ran its course.

Turnbull, who maintained he was unaware of allegations that Barnaby Joyce was the father of his staffer’s child, despite staff turnover in his former deputy’s office, said Shorten must say “what he and his office knew, and when they knew it”.

“His claim that this has all come as a surprise to him is simply not credible,” Turnbull said in his first press conference since Sunday.

“The allegations are very, very serious. It shows that there is enormous enmity, that there’s a civil war going on in the New South Wales Labor party, that this this correspondence, this lawyer’s letter to Emma Husar, would be leaked.

“There are very serious allegations of financial misappropriation of money and other allegations of harassment and bullying.

“Mr Shorten has got to be upfront and tell us exactly when he or anyone in his office knew about this, when they knew it, and what did they do about it?”

Last month Buzzfeed reported that an investigation into Husar’s office began in March, following high staff turnover and allegations of bullying and harassment, when NSW Labor appointed barrister John Whelan to investigate the claims.

Shorten said he first became aware of the allegations through Buzzfeed’s media enquiry, the day before it published the story on 19 July.

Since then, further allegations have been made public, including those contained in a letter Whelan put to Husar in May, with Buzzfeed reporting Husar stood accused of inappropriate behaviour and of having fundraising monies diverted into her personal bank account.

Husar denied the allegations in the story, responding in tweets where she blamed a former staffer and his father, both of whom are involved with Labor, for the leaks. She remains on personal leave.

Albanese, who last week admitted he knew of the investigation into Husar after it was raised during conversations at the NSW Labor state conference in late June, but had not passed the information on to Shorten, said he was troubled by how much of the investigation had been made public.

“What we have here is a process in place and 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,” he told the Nine network.

Albanese did not wish to comment further when approached by Guardian Australia, but told Nine he thought the $444m grant to the Great Barrier Reef Foundation should have been the bigger news.

Husar holds the western Sydney seat of Lindsay by 1.1% and it is not considered a safe Labor electorate.

For that reason, Labor has pushed back against calls for Husar to quit, given a byelection would be costly both in expense and potentially, party unity.

“It probably doesn’t matter what the report says now, she’ll end up in the backbench not contesting the next election,” another party source said. “It has passed the point of no return.”

A spokesman for Shorten declined to comment.

NSW Labor representatives did not respond to requests for further comment on Friday, but on Thursday told Buzzfeed the party had concerns over how much of the investigation and the allegations had been made public.

“The continued speculation about this matter in the public arena is of significant concern. It is a cause of some delay to the process and is serving to escalate tensions in an environment where parties to the assessment have expressed concerns about the impact of this matter on their wellbeing.

“The independent assessment is reaching its final stages and NSW Labor expects to be briefed by Mr Whelan in the coming weeks. NSW Labor will not be commenting on any matters which may be before the independent assessment.”