Prime Minister Jacinda Ardern has condemned rumours her Government withheld information on Auckland's latest cases of COVID-19.
Auckland entered Alert Level 3 at midday on Wednesday after four members of the same family tested positive for the virus, with no apparent connection to overseas travel or border facilities.
The rest of New Zealand will go to Alert Level 2.
The shift of Alert Levels was announced at 9.15pm on Tuesday with less than 24 hours until Auckland went back into lockdown.
In a press conference on Wednesday Ardern rubbished rumours her Government had withheld information on the new cases.
"I have heard suggestions we may have had this information earlier than we said we did. There is absolutely no reason why we would ever do that," she told reporters.
"We moved very quickly, including to inform the public and I do worry that those theories do nothing to support what needs to be collective action from all of us."
Director-General of Health Dr Ashley Bloomfield backed up Ardern's reassurances, saying as soon as he was made aware of the positive test, he leapt to action.
"I received a text from the chief executive of Counties Manukau District Health Board, she's the lead for the Auckland Region on the COVID response, at 2:40pm yesterday afternoon," he said.
From there it was all hands on deck - he says he called back, then entered a Zoom meeting to organise the next steps with the wider teams.
"We needed to have a certain amount of information to inform what are already quite significant decisions about moving Auckland to Alert Level 3 and the country to Alert Level 2," he said.
Bloomfield said the first positive case had to be re-tested and interviewed, as the rest of the family was tested too.
Ardern then talked through her timeline, saying she was first told of the positive test around 4pm while she was in Wanganui.
"I immediately spoke to my chief of staff and the health minister - I confirmed additional testing was being done to confirm it wasn't a false positive which we've had in the past,"
She arrived at Parliament around 7pm, immediately met with the Minister of Health and other experts, and then called Ministers with power to inform what needed to be done, then called the leader of the Opposition Judith Collins to brief her.
"I gave her quite a fulsome briefing because I see it's been shared with the media thereafter," she said.
She also called Auckland Mayor Phil Goff before heading to the Beehive theatrette to announce the news to the public.
Under Alert Level 3 Aucklanders must stay home, schools will close except for the children of essential workers and all cafes and restaurants must only serve takeaways.
Gatherings of ten people are allowed only for funerals and weddings and people must observe physical distancing of 2 metres.