It was refreshing.
After weeks of media coverage suggesting Ardern's pregnancy meant she was now a shoo-in to lead the Labour-NZ First coalition to win another term at the 2020 election, an Opposition politician had finally broken cover from their self-imposed PC straitjacket.
Others might have a problem taking on Ardern out of concern that they would look heavy-handed or be seen to pick on the young, pregnant woman.
But Collins said: "I have been pregnant running a law firm and studying as well. As a young mum I understand exactly how tough it is to do that. But she understands that too.
"That is not the role she's asked New Zealanders to support her for.
"She has asked them to make her and keep her as Prime Minister of New Zealand.
"And that is the role I would hold her to account for."
Collins' forthright attack has clearly resonated within the ninth floor of the Beehive.
It was notable that when Ardern addressed senior members of the Auckland business community at breakfast yesterday, she was completely on song in delivering a speech that set out the Government's focus for the next three years.
She gave a polished and confident delivery.
The positions she staked out indicate that the Coalition plans major change in the way the economy is governed.
That is coupled with a commitment to maintain budgetary responsibility — subject to the usual caveat that the Government's intention to get debt down to 20 per cent of GDP over time is also subject to the economy not being knocked by more major earthquakes or a disaster like the global financial crisis.
She positioned New Zealand as having the opportunity to brand itself in the climate change space. There are issues about just how that exciting aim will be implemented. But Labour — which she admitted was not prepared to be in Government — has time to work that out.
Importantly, Ardern issued an invitation to business leaders to put their hands up and join her in an informal group to work alongside her on delivering on her goals.
Some already have.
Notably, there was no mention of her pregnancy. Nor were there any jokes about Clarke Gayford — the upcoming stay-at-home dad. Her Vogue cover was not mentioned (apart from a closing comment by Westpac chief executive David McLean that some of his staff were lining up for selfies with the PM who had been in Vogue).
This shift in key enabled the business community to focus on what the Prime Minister had to say.
It was an important speech that conveyed important messages. It did not warrant being buried by distraction — nor was it.
John Key's prime ministership ultimately became tarred by one too many celebrity pratfalls, which ended with him being mercilessly and repeatedly lampooned on The Late Show. But he had already cemented himself as a serious player during his leadership through the GFC.
Ardern — still establishing her prime ministerial platform — must get runs on the board while maintaining her relentlessly positive approach.
It is a balance.
Ardern's positioning as Prime Minister is at times also undermined by a media fascination which borders on being fatuous.
This was embarrassingly obvious last weekend, when Julie Bishop was questioned about the shoes that Ardern wore when she popped in on a dinner that Winston Peters hosted at his home for the visiting Australian Foreign Minister.
"Seriously?" asked Bishop.
If Ardern is to deliver on the international cachet she has already achieved as a young, progressive political leader, she should ensure her international positioning — including with Australia — stays within a prime ministerial brand.
The truth is that Collins captured a growing sentiment — that it is time for the Prime Minister to ease back on celebrification and get down to business.
This she did ably yesterday.
Collins does not quite have @DonaldTrump's cut-through in the twitterverse.
But her Thursday tweet — "No more PC virtue signalling needed. #Stronganddecisive" — had the necessary impact.
Amy Adams or Simon Bridges — Collins' two main contenders for the National leadership — have yet to achieve the same.