"This guy has then returned and expected to find his friend treading water, which he wasn't."
Police began the process of scrambling search and rescue teams (SAR) when a hypothermic man appeared in his underwear, still wearing his shoes.
"So police were called and were in the process of calling out SAR when this sodden male appeared on the wharf wearing a pilot jacket, boxer shorts and some boots."
The mildly hypothermic man was taken by ambulance to Dunedin Hospital. Dinnissen said police would be following up with those involved and called on people to take better care of their friends.
"If your mates do something like that, then raise the alarm straight away.
"It could easily have resulted in something far worse."