World record holder Ariarne Titmus eased into the 400m freestyle final at Australia's Olympic swimming trials in Brisbane on Monday, with Elijah Winnington qualifying top in the men's 400 heats.
Olympic champion Titmus won her heat comfortably in four minutes and 01.57 seconds at the Brisbane Aquatic Centre, six seconds off her world best 3:55.38, to be top seed for the final in Monday's evening session.
Titmus is ranked second in the world in the event this year behind Canadian teen Summer McIntosh, who clocked 3:59.06 at Olympic trials last month.
Lani Pallister is in line to be Australia's second women's 400m entrant at Paris, following in the footsteps of her Olympian mother and co-coach Janelle, who swam at the 1988 Seoul Games and won three medals at the 1990 Commonwealth Games.
Pallister, who has a personal best of 4:01.75, was second fastest in the heats in 4:06.69.
Former world champion Winnington swam a solid 3:45.72 in the men's 400m heats, well clear of his main rival Sam Short (3:48.66), the 2023 world champion.
The pair will likely battle for podium places at Paris with Germany's Lukas Martens, who holds the year's best time of 3:40.33.
Australian record holder Kaylee McKeown qualified second for the 200m individual medley in 2:11.98 behind Ella Ramsey (2:10.96).
McKeown, the Olympic 100 and 200m backstroke champion, is also a major contender for the 200 IM gold at Paris, having posted 2:06.99 at the Australian Open Championships in April, the 7th fastest swim all-time.
Emma McKeon, Australia's most decorated Olympic swimmer, started off strongly by topping the timesheet (56.75) in the 100m butterfly, her bronze medal-winning event at Tokyo.
Sam Williamson, world champion in the non-Olympic 50m breaststroke, clocked a personal best 58.95 in the 100m heats, more than a second clear of second fastest Joshua Yong.