Serbian Novak Djokovic was hoping to win his 21st Grand Slam at the Australian Open, starting next week, but instead of training has been confined to a hotel used to accommodate asylum seekers.

He is challenging the decision to cancel his visa after being stopped on arrival at Melbourne Airport early on Thursday (January 6).

Australian authorities scrambled on Sunday (January 9) to file a legal defence of their decision to bar entry to Djokovic over his COVID-19 vaccination status.

A vocal opponent of vaccine mandates, Djokovic had declined to reveal his vaccination status or reason for seeking a medical exemption from Australia's vaccine rules.

He broke his silence on Saturday (January 8) with a legal challenge saying he had been granted an exemption due to contracting - and recovering from - the virus in December.