Jack, a member of Australia's 4x100 metres freestyle team that won gold at the Gold Coast 2018 Commonwealth Games in a world record time, returned a positive sample for prohibited non-steroid anabolic agent Ligandrol in June.

The 21-year-old was given the maximum length of suspension for a first doping offence despite claiming cross-contamination led to her positive test, which was returned before last year's World Championships in South Korea.

In a lengthy post on Instagram, Jack, who has appealed the decision from the Australian Sports Anti-Doping Authority to CAS, again protested her innocence and hit out at the anti-doping system.

The four-time World Championships medallist is expected to testify at her CAS appeal, to be held by video conference because of the coronavirus pandemic.

An exact date has not yet been confirmed but the CAS said her appeal would be heard soon.

View this post on Instagram

Now the real fight begins. Today I received further notice in relation to my hearing at the Court of Arbitration for Sport (CAS). Nearly twelve months ago, my world was turned upside down due to allegations of using a prohibited substance in my sport. Despite a lifetime of competing clean and knowing that I had not used any prohibited substance, my life changed in an instance and I was pitchforked into an unknown world of lawyers, politics and machinations that was completely foreign to me. The process has been extremely arduous and debilitating at times. There are many aspects of the anti-doping system that are seriously flawed but possibly the worst element is the presumption of guilt that one has to bear. What sort of system infers that you are guilty of an alleged breach and the responsibility falls on you to prove your innocence? Now though, I have an opportunity to stand and fight for my career and reputation. I intend to win this fight and put myself back in the pool and reclaim my position as a member of the Australian swim team. Everyone knows what it is like to have something precious taken away from them and I am no different. However, regaining my team membership and opportunity to competitively swim again is not my sole objective. Throughout this ordeal, I have learnt a considerable amount about myself. I learnt that the purest pursuit for me was my sport of swimming. I learnt that my individuality and uniqueness was the grounds for my underlying strength. I became acutely aware of my residual determination and my absolute and all-encompassing desire for the truth to be revealed. My understanding of the value of positive mental health and the benefits of a strong and positive mind was reinforced. My belief in who I am and what I stand for was fortified and my understanding of how my message is one to be shared with others was cemented. Not everyone will fight a flawed system and find themselves ostracised from their friends and support group for something they did not do. If you do though, stand up and fight and know that your honour will always be defended if you tell the truth.

A post shared by Shayna Jack (@shayna_jack) on May 15, 2020 at 2:01am PDT

"Now the real fight begins...I received further notice in relation to my hearing at the Court of Arbitration for Sport," Jack said.

"I intend to win this fight and put myself back in the pool and reclaim my position as a member of the Australian swim team.

"There are many aspects of the anti-doping system that are seriously flawed but possibly the worst element is the presumption of guilt that one has to bear.

"What sort of system infers that you are guilty of an alleged breach and the responsibility falls on you to prove your innocence?"

Jack could be in line to represent Australia at Tokyo 2020, postponed to 2021 because of the coronavirus pandemic, if her appeal is successful.

"Not everyone will fight a flawed system and find themselves ostracised from their friends and support group for something they did not do," she added.

"If you do though, stand up and fight and know that your honour will always be defended if you tell the truth."