Libby Trickett, Cate Campbell, Alice Mills, Melanie Schlanger and Marieke Guehrer are among 12 sprinters who will race for a relay place on Australia's world titles team in Adelaide tomorrow.

Up for grabs at the SA Aquatic & Leisure Centre in Marion are berths in the men's and women's 4x100m and 4x200m freestyle relays. The target: victory in a time swifter than the 5th man or woman home at trials back in April.

Olympic 100m butterfly champion Trickett makes her official comeback race in the 100m freestyle almost two years since her last big race the other side of a short retirement that was followed by a woman's prerogative. Her 100m target: 54.99. The men's target: 48.95.  

“The trial is a great opportunity to race which is exciting for me, but having said that there is a bigger picture and this is just a stepping stone for myself and Stephan (Widmer) my coach,” said Trickett through Swimming Australia. “This is a guide post to where I’m at and what we need to work on. You obviously have a bit of an idea from training, but racing will help me find out where I’m at with my preparation, and to see how far my training has come.”

In the mix of those up against Trickett is 14-year-old Ami Matsuo from the Carlile club in Sydney, and best on the clock among the Adelaide rivals this season, 17-year-old Bronte Campbell, on 54.87. Kyle Richardson, 17-year-old Cameron McEvoy and Cameron Prosser are among those fighting for the men's place. 

The 200m relay battles will unfold on Thursday, while national short-course championships will take place at the same venue July 1 -4.