St John was called on Sunday after multiple teens reportedly fainted on a hot bus taking them back from the Soundsplash music festival in Raglan.
One of the Ritchies buses carrying passengers back to Auckland had to stop on the side of the Southern Motorway in Karaka after people "begged the driver" to pull over.
Newshub has been informed that people started "passing out" due to a lack of air conditioning.
Police arrived at the scene at 1pm, where a bus was stopped on the motorway and "blocking the road partially."
"We assisted in traffic management and ensuring the bus got off the motorway to a nearby location where it was safe to stop and empty the bus," a police spokesperson said.
When Newshub arrived at the scene, people could be seen holding water bottles and fanning their faces with their hands.
One person said the air conditioning stopped after 20 minutes of everyone being on the bus.
Another girl told Newshub the bus stopped "a couple of times" to get some food and water, then got stuck in traffic and ended up pulling over at the McDonald's in Karaka.
"The bus driver stopped a few times, we were in McDonald's for about 40 minutes because it got so intense in the bus," Emily Bowie said.
Her partner, Leo Brophy described the conditions as "extreme heat."
"Everything was set up for disaster, there was the air con, extreme heat, and then the traffic," he said.
"There were quite a few people on the bus that actually passed out, like there was one girl at the front of the bus that just couldn't handle it."
One girl told Newshub "four people fainted, a lot of us had heatstroke, panic attacks, people were sweating".
"Everyone was like half-naked on the bus," she added.
The group said they had a message for the bus organisers.
"They should check if the air-con is working on a bus if it is full of sweaty kids."
However, Bowie said the bus driver "did the best he could" in the situation.
"The bus driver was good, and he stopped when we needed to, it wasn't his fault," another girl added.
St John said in a statement it sent an ambulance, a rapid response vehicle and an operations manager to the scene.
"Today in Karaka, we just had a bus travelling up from Raglan from Soundsplash. The bus overheated and had about 50 kids," St John watch operation manager Danielle Swart told Newshub at the scene.
She said the patients had suffered from symptoms of being in the sun, having no food and water and getting "a bit hot".
"We assessed all the patients and made sure they were all safe," she told Newshub.
"A full bus was affected but we only looked at about six patients."
Soundsplash told Newshub it "extends our sincere apologies to those attendees who experienced distress and who were inconvenienced by the air conditioning malfunction on one of the buses returning to Auckland today".
"We are awaiting the bus provider's full report on today's incident and, as part of our post-event analysis, we will be reviewing our provider and their protocols ahead of next year's festival," a spokesperson told Newshub.
"We are disappointed that this incident happened at the end of an otherwise successful festival."
Newshub contacted Ritchies who "sincerely regret the inconvenience to the passengers."
"High temperatures appear to have caused an air conditioning unit to malfunction on a bus, chartered to shuttle festival goers from the SoundSplash music festival in Raglan to Auckland," a spokesperson said.
"From preliminary enquiries it appears the air conditioning unit on the bus developed some intermittent issues about 30 minutes out of Raglan," they said.
"Concerned about the safety of passengers the driver stopped but then the air conditioning began to work again. Further in the journey it stopped functioning again in the high temperatures outside."
Ritchies said enquiries are ongoing and the bus involved won't be back on the road until it's been "checked over", and they are confident there were no other issues contributing to the air conditioning fault.
