Defending Hawaiian Ironman triathlon champion Craig Alexander is steering clear of pre-race hype about a potential one-on-one duel with fellow Australian Chris McCormack.

Alexander, only the fourth man to win the race three times, has no doubt his long-time rival will be a strong contender on October 13.

But the 39-year-old told AAP it would be a massive mistake to focus on any particular challenger.

"It doesn't matter to me whether Santa Claus is on the start line - I don't want to beat anyone more than anyone else," Alexander said from Kailua-Kona.

"I'm trying to execute the best performance ... I'm trying to beat everybody.

"I can't fixate on more than one scenario, this is more than a two-horse race.

"There are five or seven guys, maybe more, who can legitimately win."

Between them, Alexander and McCormack have won the last five men's world titles at Hawaii.

After finishing second on debut to McCormack in 2007, Alexander took out the 2008-09 races.

McCormack then executed a superb race strategy to gain a massive advantage on Alexander during the bike leg in the 2010 edition.

Alexander's fearsome run was not enough in the 3.8km swim, 180km cycle and 42.2km run event and he finished fourth.

Last year, McCormack was absent as he concentrated on trying to make the Australian Olympic triathlon team, while Alexander broke the 16-year race record.

McCormack ultimately failed to make the Games team, but won the world long-course title ahead of Hawaii.

Alexander says he is quietly confident about his chances this year and McCormack is talking up the potential to unseat the reigning champion with a strong run leg.

"I have no doubt Chris is going to be one of the main contenders," Alexander said.

"Anyone who knows him would know he's probably been planning this for a couple of years, he wouldn't have just decided two months ago to enter.

"I'm guessing when he decided to take last year out, his plan was always to come back this year.

"In the big picture, it's probably a very good plan ... freshen up physically and mentally and have another tilt at it."

Alexander won last year's title after a torrid few months where a long-term cough became so bad, it gave him a rib fracture.

He also had to overcome a difficult breakup with his long-time bike sponsor.

Alexander, nicknamed Crowie, has documented the eventful year in a new book, As The Crow Flies.

He ruefully notes that at times last year, the crow was grounded.

Overcoming several challenges and producing arguably the performance of his career at Hawaii was a major personal achievement.

"It gives you confidence that you do belong here," he said.

"Any athlete at any level has issues of self-esteem and confidence.

"When you're able to perform at a high level over a long period of time, eventually the penny drops that, yeah, you are good at this."