With a ticket to the Ironman World Championship already in his back pocket, young gun Nick Thompson is ready to take some risks in search of glory on home soil in Cairns.

Thompson, 24, is among those hoping to end Kiwi champion Braden Currie's firm grip on the men's Asia-Pacific title on Sunday.

Currie is aiming for a four-peat in Cairns as he battles contenders including Thompson, Englishman Joe Skipper and the USA's Sam Long.

Thompson is still a relative newcomer to the Ironman triathlon length: a 3.8km swim, 180km bike ride and 42.2km - or marathon - run.

But after claiming a podium finish in Busselton in December and with it a berth at the world championship in Kailua-Kona in October, Thompson is ready to stand up.

"These guys that I'm racing against, I've followed them for years and I feel like I'm at the stage where I can finally compete with them," he told AAP.

"I'm just quite (strong) all-around across all distances. I know I've got a good bike on me.

"I'm still trying to find my run legs over this distance, so that's probably something that I'm not as confident in compared to some of the more experienced guys out there.

"But if there's anywhere to do it, it'll be at this level and using the excitement of the race to find those legs."

Thompson has learned the dangers of going too hard after blowing up in April's Texas Ironman, at which he finished 15th.

"I definitely took a lot of risks there," Thompson said.

"But I'll try and find a nice middle ground.

"I would rather go for a win or a podium and fail and slip out of the slots - because I've already got one - rather than be conservative and come across the line at the lower end of the slots."

Two-time champion and women's course record holder Kylie Simpson is raring to defend her title in far north Queensland.

Cairns is not viewed as ideal preparation for the world championships, which will take place in Nice in September, given the two courses are dramatically different.

But with victory, the 41-year-old Simpson would top the Ironman Pro Series standings.

"Cairns is my favourite race," she told AAP.

"It would be brilliant to be able to have Cairns be the race that did that for me."

Dutch standout Lotte Wilms, strong-swimming American Lauren Brandon and Kiwi Hannah Berry are among the contenders.

Simpson will be one of the last out of the water, then need to chase the leaders on the bike before her running comes to the fore.

Last year, Simpson ran a two hour 51 minute marathon - 12 minutes faster than her nearest competitor.

"I always find myself chasing, and I love to race," she said.

"That for me is very easy to do. Regardless of what the swim deficit is, I'm always chasing.

"I just love to hunt them down."