National and international competitors in 31 mixed teams of four embarked on the gruelling expedition-style race in Milford Sound early today.
They will push themselves to the limit around the clock and without support over 522km of rugged alpine terrain to the finish line at Queenstown Primary School by Saturday.
Godzone event co-director Adam Fairmaid, of Cromwell, and the organising team registered competitors and checked their equipment was up to standard at the school on Easter Saturday.
"Don't go out too hard. It's a long time out there. A lot of people forget to keep a little bit in the tank and forget to race the last two or three days because they're so tired and lose focus."
Fairmaid said the teams to watch were Team Seagate, featuring Nathan Fa'avae, one of the best all-round adventurer racers in the world, and Team Subway, boasting Richard and Elina Ussher, individual men's and women's Coast to Coast winners who are husband and wife.
Fairmaid said Team R & R Sport, the other Queenstown-based team, was composed of "very strong local hotshots" Hadyn Key, Jess Simpson, Bas Smith and Mat Woods.
A Queenstown-based team determined not to lose focus is Team Proactive Physio, consisting of builder Brent Herdson, joinery business owner Marty Macdonald, engineer Bernard Robinson, with engineering and sports student Toni Keeling (20), of Auckland.
Macdonald and Robinson said they heard about the race last year and a half-joking suggestion to enter became a commitment, followed by the recruitment of Herdson. Teams must be mixed and fortunately the trio needed a girl, Keeling said.
The already fit and experienced team increased their training and altered their diets in preparation since January. Their record was racing for 19 hours in the back blocks with only two hours' sleep.
"We're all going to be helping each other through it and making sure we're eating and drinking and not getting cold," Macdonald said.