Taylor said the guide's raft had flipped and while he righted it the five passengers who had been in the raft with him swum to the riverbed for safety.
"They were in the process of getting the swimmers to the riverbed and it's in that period (the safety kayaker) spoke to the guide," Taylor said.
The next time the guide was seen he was unresponsive in the water.
Emergency services were called to the scene at 11.24am - and tried to administer CPR to the guide. Three ambulances and a rescue helicopter attended the incident.
Queenstown Rafting earlier told Newstalk ZB a guide had suffered a medical emergency, and had been flown to the Lakes District Hospital.
Taylor said it was a "devastating thing" for the staff and tourists to go through.
"We're in communication with them and we've been supporting them throughout the day and we'll be following up with them in the next 24 to 48 hours to make sure we've given them as much support as possible," he said.
"It's really gutting and devastating."
He said it was too soon to tell when business would reopen. It had suspended for the day.
"Our priority is to support the guides and our staff and customers who were part of this incident. We'll deal with (business) in the coming days."
In an earlier statement Taylor said the guide was the company's most senior and experienced guide, and was well loved and highly respected.
"We are all devastated and staff have been offered support. All rafting operations have been suspended," Taylor said.
The man was one of three experienced guides who went onto the river with 11 passengers at 8am.
The guides were halfway through the trip, and had just travelled through one of the rapids in a section known as the "mother", when the incident happened.
Police were investigating and Maritime New Zealand and Worksafe had been notified.
Queenstown Rafting would also carry out its own internal investigation, Taylor said.
"The company will be providing full assistance to the authorities. A full internal investigation will also be conducted."
Police said they were working with the Maritime Safety Authority and the company to determine how the incident unfolded.
Police said their thoughts were with the man's family and his death has been referred to the coroner.
In 2008, a Chinese tourist in her 40s was trapped under a jet boat after it flipped over on the Shotover River near Queenstown.
In 2001 a woman died on the river when a raft hit a boulder and overturned. Yoly Chi was trapped in the raft and didn't survive the incident.