Australia will be the only country represented with a full quota of six triathletes on its team after the final chase to secure valuable quota points went down to the 11th hour.

And according to Triathlon Australia's performance director Justin Drew it will not only provide his team with a level of protection over the three medal events but also extra options in the bid to build on the relay gold won by Birtwhistle, Ashleigh Gentle, Matt Hauser and Gillian Backhouse at the 2018 Commonwealth Games.

"It's been quite the ride to qualify three men and three women, and we are the only country in the world to do that," Drew said on Triathlon Australia's website.

"I know sport is about performance and we've got a job to do in Tokyo but outside that it means two more triathletes get an Olympic experience, and two more athletes will have the honour of representing their sport and their country and that should not be lost given the period we have been through.

"What it also gives us are the options that we wanted to ensure we had on the ground in Tokyo and some protection around relay performance which is obviously a major priority for Australia.

"So given the impact COVID will have on the (Olympic) Village, competition rules, and the late athlete replacement policy, having those six athletes in the village provides us an advantage over other nations.

"There are a couple of different regulations that are in place around Tokyo but the most significant one is the timing of the late athlete replacement around the relay. The window for that to be done based on medical considerations closes just over two days out from competition.

"That could mean if you only have four athletes (two female and two male) and once you are in that two-day window that it is very difficult to account for anything unforeseen and your team may never make the field of play."

Birtwhistle, 26, of Launceston, is among the triathletes already assured of a spot on the Olympic team, and has competed in Japan and England in recent weeks, basing himself in Spain before heading to Japan.

Meanwhile, the competition scramble for Olympic qualification points for national federations came down to a nail-biting affair after young guns Jaz Hedgeland, of Western Australia, and Queenslander Luke Willian earned maximum points with their victories in the Oceania Triathlon Championship in Port Douglas at the weekend.

Hedgeland's victory confirmed Australia had earned three female quota spots - and even though Willian also won, it was still mathematically possible for Australia to drop out of the top 30 in the last World Triathlon race of the period.

All eyes turned to Mexico and Sunday's final race of the qualifying period - the World Triathlon Cup Huatulco with Australia's Aaron Royle and local hero Cristano Grajales facing off for the much sought-after points.

If Grajales made the podium, Royle would have to finish in the top seven to earn enough points to keep three Australians inside the top 30 and squeeze the Americans out.

Having flown in from Spain, Royle woke up with a stomach upset and was forced to withdraw from the race in the early stages but Grajales could only finish seventh, leaving Australia with a narrow six-point gap over the Americans.