Ariarne Titmus almost breaks her own world record at Olympics 2024 trials as Australian superstar sets her stall for Paris Games

Australian swim stars Ariarne Titmus and Kaylee McKeown have threatened but fallen just shy of world records at the Olympic trials.

Titmus came agonisingly close to breaking her own 400 metres freestyle benchmark on Monday night at the Brisbane Aquatic Centre.

She clocked three minutes 55.44 seconds and was under the pace of her global record of 3:55.38 set last July until fading over the final 10 metres.

'You don't really think about those things,' she said of the record.

'The goal isn't just doing my best here. The goal is just to book your ticket. So I am excited to see what I can do now in Paris.'

McKeown then produced a stunning swim in the women's 200m individual medley, setting a Commonwealth record of 2:06.63.

The world record, created by Hungary's Katinka Hosszu in 2015, is 2:06.12.

McKeown's time is the fastest in the world in the event this year but, like Titmus, she said the record wasn't a target.

'It's always hard to tell when you're in the middle of a race, you kind of just switch off,' she said.

'I focus on not trying to get DQ'd (disqualified).

'It felt as good as it could be.'