Australian swimming head coach Jacco Verhaeren has backed Olympic champion Horton to rebound at next month's world titles in South Korea, naming him in the team despite not meeting his strict selection criteria.

While world backstroke champion Emily Seebohm was a big name omission, Horton got the nod in Australia's 27-strong squad despite underwhelming trials form.

The top two in each final in the six-day trials in Brisbane which concluded on Friday night earned selection providing they also finished under the tough qualifying time.

Horton failed to do either in the 200m, 400m and 800m but still had his name read out with the Dolphins team.

Yet Verhaeren had no regrets for using discretionary powers to inject the Rio 400m gold medallist into his squad.

Horton is expected to feature in the 4x200m freestyle relay team and earn an individual 400m freestyle start in South Korea.

Verhaeren was confident Horton would come good after speculating that the Victorian had struggled to adjust to his new program since ditching the 1500m last year.

"He may not have been rested enough. I am guessing here, there is no clear answer," Verhaeren said.

"But there is no concern that he can't return to his level. He is showing great training results, it just isn't translating into competition yet."

However, Verhaeren believed it was just a matter of time before Horton regained his mojo.

"Obviously he is disappointed that he is not swimming the time that he had in mind (at trials)," he said.

"But he is an Olympic champion, it's not panic stations - he could turn it around in weeks."

While Horton dodged a bullet, Seebohm wasn't so lucky.

The 12-year national team veteran missed the world titles cut after sensationally missing a top-two finish in the 100m and 200m backstroke.

Seebohm had been aiming to not only make an unprecedented seventh world titles team but also become the first woman to win three straight 200m backstroke world titles.

There were still plenty of highlights for Verhaeren.

Ariarne Titmus (400m freestyle) and Mitch Larkin (200m individual medley) both set new Commonwealth records at the trials.

Larkin also fell short by 0.27 of breaking the 100m backstroke Commonwealth record.

Emma McKeon was another standout, winning the 100m butterfly and claiming an upset 200m freestyle win over Titmus, falling just 0.25 shy of the Commonwealth mark.

Rio champion Kyle Chalmers won the 100m freestyle in a personal best 47.35 seconds to earn the No.1 ranking ahead of the world titles.

Cate Campbell consolidated her world No.1 ranking with a scorching 52.12 seconds to win the 100m freestyle.

And Matthew Wilson was on pace to break the 200m breaststroke world record for 175m before fading.

Australian Associated Press