World and Commonwealth Games champion Mollie O'Callaghan led prelims with a 53.52, just a few tenths ahead of Shayna Jack (53.72) and Emma McKeon (53.81).
Olympic swimmer Madi Wilson has revealed to SALIFE her personal battles, including developing an eating disorder, in the lead up to the 2020 Tokyo Olympic Games trials.
Shayna Jack is putting her sprinting prowess on display at the New South Wales Championships, following up her day one 100m free victory with a 50m free gold.