Late last week, the Ministry of Health incorrectly advised everyone in West and South Auckland to get a Covid-19 test, even if they don't have symptoms.
That advice was deleted three days later after Ardern said that the information was wrong.
It was also published on the Government's official Covid-19 social media channels.
Speaking to media in Auckland this afternoon, Ardern distanced herself – and her ministers – from that message, which she said was published by officials.
She said if that was the message from the Government, it would be something that would be announced "directly".
"I can assure you that if we were going to do something so significant as asking hundreds of thousands of people to be tested ... we would not leave a message as significant as that to a website, to a Twitter account or Instagram."
When asked if that included the Ministry of Health website, she doubled down – "or from a website".
"You will continue to see consistent messaging from us," she said – "us" meaning her ministers, or director general of health Dr Ashley Bloomfield.
At the Government's 1pm press conference today, Health Minister Chris Hipkins said neither he, nor Ardern, saw the message before it was published.
"There is some sensitivity around paid advertising at the moment, as we're in the regulated period," Hipkins said.
"I think that meant that officials didn't run the wording of those advertisements past us in a way they would have done previously."
He said he has since told officials that he wants that sort of information to be run by him from now on.
"These are not political advertisements, these are factual advertisements – we want to see them before they are going out.
"That last set of eyes sometimes spots things that everyone else in the chain might not have seen."
Ardern also said she had moved "very quickly" to correct the information.
She said she found out about a Unite Against Covid-19 social media post advising of the mass testing on Sunday morning at 10am.
Ardern told officials to fix it – but the post remained up until roughly 1.30pm that afternoon.
But the incorrect information was first published in a Unite Against Covid-19 email on Wednesday night.
That message was repeated on Friday – this time on the Ministry of Health's website.
"If you're in South or West Auckland, or if you have a greater risk of poor health outcomes if you were to get Covid-19, even if you don't have symptoms, please have a test," according to an archived web page.
It has since been removed from the ministry's website.
