Australia's Lani Pallister withdraws from 1500m freestyle after testing ...

Australian swimmer Lani Pallister has withdrawn from the women's 1,500-metre freestyle at the Paris Olympics after testing positive for COVID.

Pallister, who had been rated a genuine medal chance in the event, is isolating at the athletes' village.

The 22-year-old travelled to the Paris La Defense Arena on Tuesday morning ahead of her scheduled heat.

But after warming up in the training pool, an off-colour Pallister decided to withdraw from the event.

Pallister remains hopeful of taking part in Australia's 4x200m freestyle relay team on Thursday. She also has 800m freestyle heats on Friday.

The Sydneysider is coached by her mother Janelle Pallister, a Seoul 1988 Olympian and Auckland 1990 Commonwealth Games gold medallist, and is also the daughter of champion surf lifesaver and triathlete Rick Pallister.

Pallister's path to Paris has been complicated: she has undergone surgery for supraventricular tachycardia, which can cause an irregular heartbeat, and also returned to elite swimming after being diagnosed with an eating disorder.

Her positive test follows five members of Australia's women's water polo squad who also contracted COVID before competition started at the Olympics.

AAP