People at a kapa haka festival in Hamilton last weekend could be at risk of catching measles after someone who was highly infectious attended the gathering.
Waikato Population Health says the person was at the Tainui Waka Kapa Haka Festival at the Claudelands Events Centre on Saturday.
About 5000 people were at the festival, with groups from Coromandel to South Waikato competing.
Medical Officer of Health Felicity Dumble said it took about two weeks after being exposed to measles for any symptoms to show.
She said anyone worried they may have measles should contact their doctor before going to a clinic as the disease spreads very easily.