St John has revealed a total of 191 people were treated by medical staff during Juicy Fest events in Auckland and Wellington over the weekend.
"First aid and clinical treatment" was provided at both events on Friday 5 and Saturday 6 January.
It comes after police were assaulted at both cities' events, and reports of gang fights at Wellington's.
Three police officers were assaulted and 12 people arrested after "several disorder events" during Auckland's Juicy Fest concert on Saturday.
St John event health services national operations manager Natalie Lang told Newshub that 110 patients at Auckland's concert required on-site treatment.
Meanwhile, 81 people were treated by St John staff during Wellington's event - where six arrests were made following "fighting and disorderly behaviour".
"There were several incidents outside the venue, and police had a strong presence to address any issues," a police spokesperson said.
"Officers dealt with several reports of intoxication, disorder, and assault involving people outside the event, including suspected gang members."
Police said one officer was hit with a bottle and injured, leading to the arrest of one man.
"Both nights were steady and in line with what we would expect at events of this nature," Lang said.
She said the majority of incidents were related to minor ailments, including "small cuts, headaches, dehydration and sprains".
"Only one patient was transported to hospital in Wellington in a serious condition," she added.
Four patients were taken to hospital in Auckland, where one was in a serious condition and three were in a moderate condition.
