A bus passenger took control of the steering wheel after an InterCity driver appeared to have a panic attack after pulling the bus over three times.
A passenger told Newshub the Wellington-Auckland bus trip turned sour after a driver change in Taupō.
"The driver was saying that he did not know how to drive manual, so he was just getting taught how to drive manual in that moment," she said.
He couldn't stop the bus at the first intersection and passengers started to fear for their safety, she said.
The panicked driver stopped on the side of the road, but was sweating and crying as he rubbed his head with his hands.
And the second attempt on the road didn't fare any better.
"This time was bad," the passenger told Newshub.
"He was crying, freaking out."
Another passenger took control of the steering wheel, but could not legally drive the bus-load of passengers.
InterCity investigated the incident and said the passenger was qualified and only "temporarily" drove the bus, the company told Stuff.
It comes after a Facebook users alerted the incident on social media.
"InterCity bus driver has fallen sick while driving, now a passenger is driving the bus SH5 heading towards Rotorua," the person said.
InterCity confirmed one of its drivers on Saturday night replaced the original driver, who had earlier fallen ill.
• Bus passenger takes steering wheel after InterCity driver falls sick
• Editorial: Intercity bus depot in south a wrong move
• Boy 'gobsmacked' at being left behind at Bombay service station by InterCity bus, says passenger
• Passenger says Intercity bus driver who left boy behind on toilet stop had 'very heated conversation' with boss
An InterCity spokesperson said the service was continuing through to Auckland, "albeit delayed".
"It appears that the original driver may not have followed company procedures when starting to feel ill," the company told Stuff.
"A passenger who temporarily drove the bus was a qualified bus driver with the appropriate licence endorsements for a large passenger vehicle."
An investigation is under way to learn more about the incident and identify any follow-up actions, InterCity said.