World champion Ariarne Titmus dominated the women's 400m freestyle on Saturday morning at the Gold Coast Aquatic Centre, to back up her success in the 200m freestyle title two days ago.

The 20-year-old won in 4 minutes 1.34 seconds to finish well clear of Leah Neale and Kareena Lee - who has already secured her spot for the Tokyo Olympics in the women's 10km event.

Titmus was happy to be back and performing at an elite level, in the lead-up to June's Olympic trials in Adelaide, in her first real competitive hit-out since taking some time out of the pool due to a shoulder injury.

"For me I know what a 400 should feel like and what I have to do to in terms of the race and my breathing patterns and the feeling in the water, so that's something I had kind of forgotten a little bit," Titmus said.

"I was a bit nervous coming into this race and whether I was going out hard enough - I had lost a bit of confidence to go out hard, especially after my injury, but I feel like I got that back today.

"Racing well gives you the biggest confidence leading into the next meet so I'm happy that I've ticked off what I needed to do here for those races."

Mitch Larkin fired a warning shot to the swimming world, clocking 1:56.74 to win the men's 200m individual medley in the fastest time of 2021.

"It's one thing to look at the times but in work, at meets like this, it's about really pushing your comfort levels as much as you can... It's about emptying the tank and we'll look at the skills and stroke and technique over the next eight weeks," Larkin said.

Emma McKeon continues to showcase her class in the pool, capturing her sixth Australian gold medal in the women's 100m butterfly, the 200m backstoke was won by Emily Seebohm while Kaylee McKeown took out the 200m individual medley.

In Saturday's other finals, Tristan Hollard added to his 100m backstroke crown with victory in the 200m with a personal best of 1:56.40, Elijah Winnington defended his title in the men's 400m freestyle while Matthew Temple won the 100m butterfly.

Australian Associated Press