"This event was my first real trail run," says Mr Smith.
"My biggest achievement is an eight-day race over 800km in the USA, but that was a lot of flat open spaces.
"What I love about trail running is that there is something different around every corner, especially on this route."
Entrants can run 60, 85 or 100km and all courses will pass through native bush, exotic forestry, lakes, waterfalls and along the Tarawera River tracks.
Mr Smith is hoping to finish the race in less than 11 hours, gauging his time by comparing himself with top international athletes.
Entrants like Mr Smith prove that although it is a tough and exhausting run, people do not need to be super-athletes to enter.
"I'm a fifty-per cent man. I look at the time the top guys do it in and double it," he says.
Mr Smith took a well-deserved rest late last year, after running the equivalent of three marathons over six weeks, and has had to put in some extra effort in the lead up to the Tarawera Ultra.
His race preparation includes a memorable 32km race in the Coromandel where Mr Smith managed to trip on a tree root, banged his head and arrived at the finish line bruised and bloodied.
"If you haven't done the work, you get what you deserve. Although last year I felt a bit hard done by because I ran the race on only two hours sleep after being kept awake by a loud party next door," he says.
Entrants are rewarded throughout the course with a vast array of goodies at numerous aid stations, generously sponsored by a range of local businesses.