Detective Sergeant John Wilson, who leads the Rotorua police Search and Rescue team, said a search of the river began immediately by locals, rafting crews in the area and emergency services.
The man's body was found by staff from a local rafting company about 3.40pm.
"The group got into some distress and as a result two were rescued by other people swimming in the area. Unfortunately one of the group went under."
Mr Wilson said if it weren't for the quick thinking of two people in the area, the other two men could have drowned also.
"If they had not intervened we would have had three people dead instead of one," he said.
The three men were described as being of Indian descent but it was not yet known if they were locals or visiting Rotorua.
The dead man's next of kin were in India and his name would not be released until they had been informed.
He said the Trout Pool area was a reasonably wide part of the river at the bottom of the rapids where the rafters came out. He said the popular swimming spot was slow flowing and deep.
He said the drowning would now be referred to the coroner.
Raftabout co-owner Steve McNab said one of his crews were first on the scene to help look for the swimmer after a woman from the group ran up to them and asked for help.
"I was called by the guys because I was back at base. But they told me they dropped everything and went to help. Sadly, it was too late for one of them," Mr McNab said.
"The boys took a kayak down, and then a raft, and started searching. It's pretty deep in the Trout Pool and we understand the swimmer had no buoyancy.
"It's really unfortunate, but a lot of people swim out there, it's not a dangerous part of the river, it's quite slow moving and calm. But quite clearly they could not swim and if you can't swim then any water is dangerous," Mr McNab said.
A hearse arrived at the site about 4.30pm to take away the body.
Touring couple Josh and Ray, who didn't want their surnames published, said they had been swimming in the area last night around 6pm, along with about 10 local children jumping off the bridge and a couple of tourist families.
"The current was strong but you could swim out of it," they said.
Three Indian nationals have drowned in the Bay of Plenty area since 2010.
The deaths prompted the Rotorua Aquatic Centre to educate the city's migrant community on water safety at the end of last year by employing an Indian swim instructor.
- additional reporting by Matthew Martin and Shauni James
* Narayan Kumar Daggumati, 29, drowned in Lake Tarawera
on January 3, 2009.
* Sumit Goel, 22, drowned at Ohope Beach in February 2011.
* Sidhant Sharma, 21, a Waiariki Institute of Technology
student in Rotorua drowned on Lake Taupo in March 2014.
