To be thrown out of an overturning boat in such circumstances was also "very serious and can be life-threatening".
Police were alerted at 12.35pm that a boat had overturned and the rescue was completed about 1.30pm, all three occupants safely being located.
The boat was believed to be a small powered boat which was apparently trying to return across the Taieri Mouth bar, perhaps after a fishing trip.
Mr Gale said a rescue helicopter had flown to the area and lowered two water rescue squad members down to the overturned boat, to check if anyone was trapped underneath it.
No-one was beneath the boat, which apparently had been near Taieri Island.
One of the boat’s occupants was also winched to safety, and was apparently flown to Dunedin Hospital with hypothermia.
Mr Gale was pleased that the rescue helicopter had been part of a successful collaborative rescue.
"It’s very much everyone is there to support one another, whatever the best way to do that."
A police spokeswoman said the fishing boat had also played an important role in the rescue, and had helped to uplift people from the boat.
Police have previously said that Taieri Mouth and its bar is a "very well-known hazard" and "one of the most dangerous waterways on the Otago coastline".
