He said his body was up for the challenge.
"It comes down to mind over matter and a lot of caffeine pills," he said. "I think I am the only person to have attempted it."
The official Motu Challenge starts at 7am tomorrow, with competitors racing in teams or as individuals. This year is the 20th annual Motu Challenge and features a 65km mountain bike, 17km run, 52km road cycle, 27km kayak, 8km road cycle and a 3km run to the finish.
Townley said he hoped to finish his first lap early tomorrow morning to give him time to have a quick sleep before the official race began.
He estimated his overall time to complete the two laps would be between 23 and 25 hours.
"I'll be looking forward to the beer at the end," he said.
He said he had been labelled "crazy" many times before, but it didn't stop him. "I have been called that many a time along with a few other things."
Townley, who is involved with the Rotorua Association of Triathletes, said about a dozen local athletes were taking part.
A separate 2013 Motu 160 Cycle Challenge is also being held tomorrow for road cyclists.
Being a typical Rotorua multisport athlete, Townley said his favourite discipline was the mountain bike.