Kaylee McKeown shatters yet another swimming record but Australia star makes surprise revelation ahead of Paris Olympics

Backstroke star Kaylee McKeown has declared her foray into the women's 400m individual medley as 'one and done' despite breaking a Stephanie Rice record for the second consecutive night.

McKeown bettered Rice's Australian record in the women's 200m individual medley on Wednesday night.

And she was at it again on Thursday, coming up trumps in the 400m individual medley in yet another record-breaking display at the Australian Open Championships on the Gold Coast.

McKeown's time of 4:28.22 smashed the mark of 4:29.45 set by Rice at the 2008 Beijing Olympics.

So it begs the question, will McKeown add the 400m individual medley to her schedule for the 2024 Paris Olympics?

'Nope. One and done. That's me,' McKeown said.

McKeown, who is keen to add the 200m individual medley to her backstroke schedule in Paris, paid tribute to Rice after breaking another of her Australian records.

'I don't think she's erased by any means. She's a legend of the sport and always will be,' said McKeown, who holds the world record in the women's 50m, 100m and 200m backstroke.

'I'm coached by the same coach (Michael Bohl), and he knows what he's doing.'

The women's 50m freestyle final produced a dead heat as Shayna Jack and Meg Harris both touched in a time of 24.28 seconds.

Emma McKeon (24.46) took out bronze, with Australian record holder Cate Campbell (24.79) missing out on a medal.

A drug ban meant Jack missed the Tokyo Games in 2021, but she's on track to make her Olympic debut in Paris.

The Australian Open Championships have no bearing on Olympic selection, with the trials for the Paris Games to be held in early June in Brisbane.

'I think for any of us it would be fantastic, and for me personally it would be special to say (I'm an Olympian),' Jack said.

Olympic champion Zac Stubblety-Cook (2:07.5) survived a major scare to pip Japan's Ippei Watanabe (2:07.62) in the 200m men's breaststroke.

It added to Stubblety-Cook's gold in the 100m breaststroke on Wednesday night.

The 25-year-old Australian won gold and set a world record in the 200m breaststroke at the Tokyo Games.

His world record has since been broken, and Stubblety-Cook wants it back.

'I had a taste of the top,' he said.

'You get to the top and realise how good it is. You desperately want to get back there.'

Elizabeth Dekkers (2:05.20) beat Brianna Throssell (2:06.98) in the women's 200m butterfly.