There are now 11 cases of COVID-19 connected to the Soundsplash music festival.
Newshub understands a group of 11 friends have now all tested positive since attending the event in Hamilton at the weekend - two of them have been told they have the Omicron variant.
With 8500 festivalgoers, all in close proximity and most without masks, the festival was always a risk.
Auckland resident Emma, who is 17 and double vaccinated, got a test after feeling unwell on Tuesday, then Wednesday she got a call to say it was positive.
"I've got pretty horrible fevers, chills, headaches and I'm coughing and I'm sneezing," Emma told Newshub.
Genome sequencing has now confirmed she has Omicron and she says 10 of her friends have now tested positive too.
"Yeah, I think it definitely has the potential to be a superspreader event. If COVID was there then I think pretty much everyone will probably get it."
Epidemiologist Professor Michael Baker says the festival could be a super spreader event.
"Ideally being outdoors should reduce transmission but unfortunately when you've got a lot of people crushing together that's still enough for this virus to transmit between people."
But while the news was spreading on TikTok on Wednesday afternoon, the Ministry of Health didn't list Soundsplash as a location of interest until 10:30am on Thursday.
In a statement the Ministry of Health said the priority at this stage is identifying close contacts who are most at risk, and ensuring they isolate and get tested.
"Health officials work at pace to collect relevant information to carry out a risk assessment and subsequent decision-making. This can take time."
But it was too late for schools. Auckland Grammar took the matter into its own hands and asked 120 boys who attended the festival to stay home.
"We didn't have any advice so we acted in a manner that was in the best interest of our community and that was to produce a negative covid test before returning to campus," said Auckland Grammar School headmaster Tim O'Connor.
"It's about being socially responsible because they are going to be coming back into a school community of 2600 and 250 staff," said O'Connor.
"I would have prefered it to be named as a location of interest as early as possible and to be later removed if that was the case."
Sixty-eight people who went to the festival have been identified as close contacts so far and the Ministry of Health says other attendees should self-monitor for symptoms.