TRIATHLON: Saturday's fourth round of the World Series in Yokohama, Japan is the last chance for Australian triathletes to stake their selection claims for the Olympics.

Beijing bronze medallist Emma Moffatt, already a confirmed Rio selection, will lead a team of five women and two men at Yokohama.

Australia has won at least one medal in every Games since triathlon made its Olympics debut in Sydney.

The women have done the heavy lifting, winning all five medals.

But in the lead-up to Rio, the Australian men are showing stronger form and TA performance manager Bernard Savage concedes the women need to step up.

"The one thing that is most apparent is if you have a discipline that is not up to standard then you will be exposed - there is nowhere to hide," said Savage.

"You have to have a strong swim, bike, run.

Some aspects have been good with the women, but there has to be improvement overall to match it with the best in the world."

TA selectors must submit their nominations - three men and three women - to the Australian Olympic Committee by next Friday.

Aaron Royle and Ryan Bailie are confirmed members of the men's team.

Moffatt is the only woman to have locked in her Rio berth and the other three nominations will come down to selectors' discretion.

Ryan Fisher and Jake Birtwhistle are the Australian men racing at Yokohama.

Given Fisher finished fifth and Birtwhistle was ninth last month at the Gold Coast round of the World Series, Yokohama probably represents a head-to-head duel for them to see who takes the third men's Rio berth.

Ashleigh Gentle has strong claims for one of the two women's vacancies, as she was 15th on the Gold Coast and second at the opening World Series round in Abu Dhabi two months ago.

But it is an open field among London bronze medallist Erin Densham, fellow 2012 Olympian Emma Jackson, Gillian Backhouse and Charlotte McShane for the third berth.

AUSTRALIAN OLYMPIC TRIATHLON MEDALS
Sydney 2000 - Michellie Jones (silver)
Athens 2004 - Loretta Harrop (silver)
Beijing 2008 - Emma Snowsill (gold) and Emma Moffatt (bronze)
London 2012 - Erin Densham (bronze)

AAP