Complicating matters is the inclusion at the Games of the mixed team relay, in which two men and two women compete. With a maximum of six spots across the two individual races, selection becomes a more difficult equation.
That equation can be simplified on Sunday but it will be far from easy for the athletes, the lofty standards for automatic nomination set by Triathlon New Zealand ensuring expectations remain high.
"It's one of the things that came out of our [Olympic] review - we wanted to have tough criteria because we set our expectations high," said national coach Greg Fraine.
"The athletes are accepting of them and they understand what needs to be done and they're aiming for it.
"It's very tough - I'm not saying that we've got anybody who's going to walk into the top eight positions. They're going to be fighting all the way to get there."
The only athlete without a fight on her hands is Hewitt, after an eighth-place finish in last year's grand final race in London.
Samuels barely missed qualification at the same event, while McIlroy was working her way back to full fitness after surgery in the off-season.
"There's no expectations around [McIlroy] as far as putting a medal-winning performance on the line on Sunday," Fraine said.
"It's about getting her ready for Glasgow.
"[Samuels] has got some good results and it just comes down to discretion now around those results. The top eight qualifies them and then everyone else is in the same situation - it comes down to the selectors' discretion."
Tony Dodds is another man who will be subject to that discretion, after his strong recent performances were curtailed by an elbow injury suffered at last month's world cup race in New Plymouth.
ITU World Triathlon
Auckland - Sunday
• Elite women, 12pm, Queen St course
• Andrea Hewitt, Nicky Samuels, Kate McIlroy, Simone Ackermann, Rebecca Clarke, Fiona Crombie, Anneke Jenkins
• Elite men, 3.30pm, Queen St course
• Ryan Sissons, Martin Van Barneveld, Bryce McMaster, Tom Davison, Cameron Goldsmid.
