The event has been thrown wide open in the absence of last year's New Zealand winners Richard Ussher and three-time women's champion Gina Crawford.
Changes to the 180km bike-leg will add a fresh approach to the 226km race and perhaps discount the experience factor for five-time returning athletes, such as Luke Dragstra and Petr Vabrousek.
Dragstra, the winner in 2007, said the solitary aspect of the day-long event could play mind tricks with athletes.
It took mental fortitude and endurance stamina to keep pushing the pace when you were out on your own, he said.
New Zealand athlete Keegan Williams will carry local hopes in the event and the Cambridge-based athlete said he was showing good form, during a Challenge Wanaka media conference this week.
He came third in the Port of Tauranga Half Ironman race last week and has an eye on keeping his hydration levels up during Wanaka, after he staggered over the line and faded badly to finish third last year.
The changes to the bike leg meant a hilly section of the cycle would be over early, but the changes would not have a major influence in the overall scheme of the race, he said.
Weather conditions would be the only thing with the potential to affect race strategies. The forecast northwest wind was a factor which everyone would have to contend with, Williams said.
The female race has an aspect of musical chairs to it this year with the late withdrawals of several top athletes, including Crawford, and the subsequent last-minute entries by replacements.
Her competitors consider 2007 winner Belinda Granger, of Noosa, Australia, the benchmark athlete in the women's race.
Aucklander Belinda Harper, who will be the sole Kiwi for vocal local supporters, is a dark horse despite her inexperience at the long-distance event.
She blitzed all comers across the age groups in her first race at the Hawaii Ironman event - considered the pinnacle of long-distance racing - where she smashed the age-group record on the demanding Kona course.
INFORMATION
• Course records: 8hr 43min 41sec, Richard Ussher (2010), 9:28.27, Gina Crawford (2009).
• Start: 6.30am Lake Wanaka foreshore.
• Swim 3.8km: leaders expected to exit the water after about 45 minutes
• Cycle 180km: Athletes will do a loop to Lake Hawea first before heading to Cromwell and back along Lake Dunstan.
• Run 42.2km: Winners expected at finish line from about 2.30pm. No change to the run course along the Clutha River's Outlet trail.
