But top whitewater kayakers have been running the canyon since 1982 - and for Sutton, a three-time Extreme Kayaking World Champion, he always wanted to take the plunge.
"Since I started kayaking I had seen amazing video footage of what seemed like near suicidal kayaking adventures in this remote region," Sutton said. "Finally, after many years kayaking, I had the courage, skill and opportunity to get in there and test myself."
Sutton grew up a stone's throw away from the Kaituna River and has described Okere Falls as his "happy place". His tour company, Rotorua Rafting, is based on the river. Whitewater runs in the blood: his brother Jamie is also a kayaker.
For the best part of a decade Sutton has competed (and won) at kayaking events around the world.
European media nicknamed him "New Zealand's Rocket" after a string of high finishes early in his career.
But in contrast to the common stereotype of a professional thrillseeker, he is known to be cautious and self-critical. In a piece of writing about tackling the Stikine, Sutton described the emotional conflict he experienced before embarking on the trip.
"It is seen as the Everest of Rivers not because it the hardest river in the world, nor is the biggest river in the world - but it is a river that will require all the kayaking skills you have in your artillery, test your nerves, character and make you question your ability to make it out alive.
"As the date arrived and we said our goodbyes to family, I couldn't help but wonder if it would be the last time I saw my daughter and partner. But this river had been a dream of mine for a long time, and if I hadn't made the trip I would have felt as though I had let myself down for the rest of my life."
Sutton has now returned to the northern hemisphere for a five-month competitive summer season, which includes races in the Alps, Norway, and at the Extreme Kayak World Championships in Austria.
"I would love to have the opportunity to win another world championship," he said. "The last years I have been teased by posting the fastest time in the semis, [so] now I just need to delay the good run for the final."
He said he was hoping to make a short trip back to New Zealand in the southern mid-winter.
After the personal triumph of kayaking the Stikine, his "happy place" was now calling him back, and Sutton hinted at a desire to cut down on the jetsetting.
"Nowadays I am based about six months of the year in Okere Falls ... I hope this increases in the years to come."