"They were three guys having a good old time but lost where the track was," he said.
Earlier in the day, the men, all aged 25 and from Auckland and Wellington, had walked from the end of Waihaha Rd through a bush reserve to the edge of Lake Taupo then followed a track up the river towards the Waihaha Falls.
A police spokesman said the men decided to jump into the river to swim the three kilometres back to the lake after they struggled to navigate the track which was overgrown and difficult to follow.
But by 7pm they were tired and cold, and still some distance from their destination.
He said they decided to get out of the river, and tried to walk to the lake, but the bush was so thick they could not get through.
With daylight running out and fatigue setting in, one of the men called his father who raised the alarm.
The Lake Taupo Volunteer Coastguard rescue vessel with a search and rescue team on board arrived at Waihaha Bay at about 9pm, but could not land on the beach because of strong winds and large waves.
Police had to use the Greenlea Rescue Helicopter to fly in a second rescue team.
After landing at about 10.30pm, the rescue team was taken up the river in a boat provided by people camping at Waihaha and quickly found the missing men.
The trio were taken out and spent the night at a local marae.