The Ministry of Health has launched a review into the blunder which saw hundred of thousands of Aucklanders wrongly told to get a Covid-19 test.
Speaking at Parliament, deputy director general of health Robyn Shearer told reporters the Ministry had "taken responsibility" for the mistake and was working to fix it.
"We will be looking in detail at how we can improve," Shearer said.
"It's around a protocol shift: so ensuring that when we're putting information up onto the website we've had the right sign-off by the public health clinicians."
Late last week, a post was published on official channels instructing people in South or west Auckland to get tested "even if you don't have symptoms".
The message was repeated on the Ministry website and on a ministry email update. It was also promoted by Healthline staff.
Shearer could not say when the Ministry review would be completed or whether it would be made public in full.
"I think we're happy to communicate the findings," Shearer said.
Speaking to media in Auckland this afternoon, Prime Minister Jacinda Ardern issued an apology to anyone who unnecessarily queued to be tested as a result of the error.
"This could have and did cause anxiety for people and I'm sorry for that. No one should have any reason to feel any extra stress than they do right now," Ardern said.
At the government's daily Covid-19 media conference, Health Minister Chris Hipkins said he was confident the miscommunication would not happen again.
"A relatively long set of guidance around who should be tested was then translated into a couple of sentences which got put into a social media ad," Hipkins said.
"I'm confident that everyone involved has learnt the right lesson... and that will be tightened up."
Hipkins said officials had failed to run the messaging past the government as they were overly cautious about the looming election.
"These are not political advertisements, these are factual advertisements," he said. "We want to see them before they're going out.
"That last set of eyes sometimes spots things that everybody else in the chain might not have spotted."
He said the issue was a matter of communication that was "lost in translation, but he was focusing on fixing the problem and ensuring it would not be repeated.
"I'm not interested in pointing a finger."
"We do want to see the asymptomatic testing coming up in those areas ... testing priorities will change depending on where we're at in the cycle."