A number of teenagers who attended the Soundsplash Festival near Hamilton at the weekend say half their friends now have Covid-19.
Some say they have been told they have omicron and there are fears the event could be the first super-spreader of the new Covid-19 variant.
Many are school students who are at or are planning to head back to school shortly.
The Hamilton event is now connected to at least five cases of Covid-19, including one of Omicron.
At least 68 close contacts have been identified - and all festival-goers have been told to monitor for symptoms, and isolate if they are called to.
Auckland's Secondary Principals Association president Steven Hargreaves is principal at Macleans College in Bucklands Beach.
He spoke to Corin Dann.