"The only thing I won't be doing (in training) is the swim, I'll save that until race day - all I keep thinking about are the crocs."
Brown backs McCormack as a favourite despite his limited preparation.
"Even though he hasn't done too much ironman training he will have a tonne of speed from racing the ITU World Championship series so he will be fast and dangerous."
McCormack played down his chances of taking the title having invested most of his efforts in his failed campaign to make the Australian Olympic team.
The trans-Tasman rivalry was always healthy and Brown would like nothing more than to snatch a win from the Australians, especially McCormack who has been an occasional training partner.
"It's always nice to beat the Aussies on their home turf but it's also very hard, and there are a number of guys that will be challenging Macca for the title," added Brown.
Some of those other contenders include Australians Matthew White, second last year, Luke Bell, a runner-up at Ironman New Zealand, and the improving Dave Dellow from the Olympic-distance ranks and Aaron Farlow, second at Ironman New Zealand.
Auckland's Simon Cochrane will make his official ironman debut in the professional ranks alongside super-experienced Canterbury Ironman, Bryan Rhodes.
Former Australian ironman champion and Cairns winner in 2011, Rebekah Keat is favourite for the women's honours from fellow Australians Michelle Mitchell and Melissa Rollinson, making her ironman debut after winning the Ironman 70.3 world championship last year.
There real interest in the efforts of Auckland's Belinda Harper, who was impressive at Ironman New Zealand this year, and Cambridge's Candice Hammond, a strong cyclist who has indulged in cross-training as a shearer to augment her preparation and bank balance.
The course comprises a 3.8km swim in Sailfish Quay, a 180km bike to Port Douglas and return and 42.2km marathon run to finish in downtown Cairns.