``There were some in the group who were in pretty bad shape. They were incomprehensible, mumbling, and their eyes were rolling to the back of their head,'' he said.
Some of them had been wearing wearing shorts and jeans, and they were all inexperienced.
Two women were taken by ambulance to Taupo Hospital with suspected hypothermia.
``It was very irresponsible of [Mountain Shuttles], from our point of view.''
The group, believed to be in their 20s and 30s, were from Auckland and of Indian descent.
Mountain Shuttles owner-operator Kevin Gardiner, who was driving the shuttle, said he did not regret taking the group to the mountain.
``It wasn't too bad when we were up there in the morning, it was just the wind situation. But I actually read them the forecast which was showers clearing in the morning, westerly strong winds - 75km wind in exposed places - gradually dying away in the afternoon. So they were well aware of that.
``I saw no issue: we're talking about adults, people that make their own decision,'' he said.
Mr Gardiner questioned whether some in the group had been wearing shorts: ``I don't know about that, I don't know, that's a very sticky one. They were adequately dressed in my opinion, they even had winter hats on.''
He had also told the group that if they wanted to turn back at any stage he would pick them up.
According to the Mountain Shuttles website, it costs $25 per person for a shuttle to the start of the hike. Trampers then hike to their cars at the other end.
Mr Owen said every transport operator in the area except for Mountain Shuttles was a member of the Tongariro Alpine Crossing users group, which sets protocols about when it is safe to do the hike.
Users group chairman Stewart Barclay said the wind speed on Saturday exceeded its cut-off of 50km/h, and the clouds and rain were also worse than the protocols allowed.
``It is every person's right for people to have free access to the national park, so it is every individual's responsibility, but as a user group we highly recommend the users to stick to the protocols,'' he said.
Mr Gardiner said he was not the only operator that took a group on the mountain that day, and he had seen a Turangi Rentals alpine shuttle heading for the crossing.
Turangi Rentals alpine shuttle manager Ross Laird said he had taken a woman to the mountain, but it was to do a far easier, low-altitude walk to a waterfall, and she was well prepared.
``I refused to take people there that day even though I had huge amount pressure put on me but I didn't buckle,'' he said.
Police reminded people venturing into the outdoors that the winter season is nearly upon us which means a dramatic drop in temperatures, especially in alpine environments.
``Ensure you have the correct equipment for the environment and always prepare for the worst weather,'' they said in a statement.
``If in doubt people are urged to contact the local Department of Conservation visitor centre for weather and track updates before venturing into the area.''
