Kaylee McKeown has carried on from where she left off at the Olympics, blasting to a short course world record in the 100m backstroke at the Australian Championships in Adelaide.

The 23-year-old, who struck double gold in Paris amid her five-medal haul last month, proved the standout again on the opening night of finals on Thursday, setting a new mark of 54.56 seconds at South Australia's Aquatic and Leisure Centre.

It eclipsed the five-year-old record of 54.89 set by fellow Australian Minna Atherton in Budapest during the International Swimming League season in 2019.

Remarkably, the Queenslander, who's already qualified for the World Short Course Championships in Budapest in December thanks to her Olympic heroics, only entered the national event because she felt somewhat bored since getting home from her Paris exploits.

"I was going a bit stir crazy, sitting at home, so decided to jump back in two-and-a-bit weeks ago, and just increasing the sessions. I don't mean to toot my own horn -but we're doing some pretty incredible stuff at training," she said.

"I'll see how I feel after World Cups (in October/November) and see if I want to do World Short Course in December, but I'm not putting any pressure on myself."

With her coach Michael Bohl taking a break, McKeown has been training under his assistant Janelle Pallister at Griffith University on the Gold Coast.

"Janelle's been an absolute legend," McKeown said of Pallister, a 1988 Olympian and mother of teammate Lani.

"She's taken us on board and obviously she's been under Bohl for a few years now, so she knows what she's doing. Lani also produced a great swim tonight, so did a few other young swimmers," McKeown noted.

Lani Pallister took the 200m freestyle title, clocking 1min 52.73sec, ahead of Leah Neale (1:53.60), with both earning their trips to Budapest.

Other record-breaking performances came from 19-year-old Edward Sommerville, who set a national mark in the 200m freestyle (1:40.64), and Josh Yong, who broke the Australian mark in the 100m breaststroke in 56.76.

A dozen swimmers registered qualifying times for Budapest including dual Olympian Isaac Cooper who clocked 50.17 to win the men's 100m backstroke.