OPINION: There are a few things keeping Jacinda Ardern up at night.

That's what she told The Washington Post in an interview this week, timed ahead of her departure overseas next week - first to Japan, then to New York for the United Nations.

The things Ardern listed keeping her up were the usual - the ability of her Government to get its ambitious plans finished in New Zealand's relatively short terms of Government - but given the last week you can be pretty sure some non-policy thoughts were intruding too.

Indeed, it has been such an atrocious week for Labour that I'm sure Ardern would be happy to be talking about the catastrophic backdown over KiwiBuild, if only as something that doesn't call into question her own integrity as person, let alone a leader.

The exact amount that Ardern knew about the serious sexual assault allegation against a Labour staffer before Monday is still murky, as is the status of the information when it got to her - was it first, second, third hand? She says that it wasn't until Monday that she learnt that the complaints were definitely of a sexual nature, but she seems to have been the last person to know.

The amount that her most trusted colleague Grant Robertson knew is similarly murky, so much so that he's refusing to answer questions about it, other than to say he is confident he has done the right thing. This is all complicated by the fact the alleged offender worked in the Labour Leader's Office, which sounds like the Prime Minister's office but is actually a whole separate entity outside of the Beehive that has little to do with her day-to-day.

Take this murkiness and throw in the fact that the complainants, who rightly feel the party has utterly failed them thus far, are motivated to dispute the lines coming from Ardern and her party, including by talking to National - and it all looks like a scandal that will continue to bleed into the weeks to come.

This could be especially problematic for the Prime Minister as she is due to fly off to Japan and then New York for the United Nations General Assembly, where she is planning a Christchurch Call event.

• How to make the Labour abuse scandal worse
• Labour staffer at centre of sexual assault claims resigns from Parliament
• Former Labour Party president surprised Jacinda Ardern wasn't told about sexual assault claims
• Haworth's resignation doesn't change anything - PM still must front up

The call - a vast and unwieldy series of pledges from both nation states and the biggest tech companies to stop anything like March 15 ever happening in such an online way again - is an important and worthy goal for the Prime Minister. But focusing on it while allegations as serious as this swirl at home will be very difficult. And it plays into a narrative that National leader Simon Bridges has been pushing that Ardern is a "part-time PM" - more interested in a glitzy overseas image than governing at home (the fawning Washington Post interview released this week didn't help.)

Bridges' unprompted attack on the Call this week, clearly part of the wider "part-time PM" strategy, suggests he sees some sort of polling gold in following this line of inquiry, and National can afford a pretty good pollster.

Last year when the Prime Minister was in New York for the same meeting the scandal du jour concerned Derek Handley in the last of many chapters in the Clare Curran saga. This is a whole new level. Robertson, who Paula Bennett says was told of the sexual assault allegation, is not a fire-able minister for Ardern in the same way Curran was.

But even the worst scandals do fade from the headlines eventually, as this one will - possibly by the time the prime minister crosses the world from Japan to New York, and New Zealand is far too busy following the Rugby World Cup.

What doesn't fade is trauma. A lot of people across this country have experience with some sort of sexual harassment or assault. They also have experience with the people and companies who constantly preach progressive politics protecting the people responsible when accusations are made.

This Government seems to recognise this - it's currently changing the Evidence Act to make it harder for defence lawyers in rape cases to use alleged victims sexual histories as ammunition. But all those people with all of that trauma have just had the bare facts of just how inadequate the party at the centre of this Government is on these matters, despite a written warning in 2017 and the summer camp scandal that followed.

Ardern was supposed to be different. She oozes approachability and sympathy. Ever since The Spinoff story on Monday she has been saying all of the right things, demanding that the QC report be sent to her not the party and clearly setting out her problems with the party's process thus far. But it's hard to escape the fact that both this response and the steps taken in early August to keep the staffer out of the workplace happened following media attention. It shouldn't take involving the media and the opposition to get movement on these things. And even if the party hierarchy - rather than Ardern herself - is to blame for this all going so badly, she is the leader of that party, and shouldn't need to separate scandals under her watch to happen to reform that system.

It might never be clear exactly when Ardern or her staffers knew what, and how much they could trust that information when they were told. But there is enough grey here to make Ardern lose a seriously large amount of trust - along with a fair bit of sleep.