Novak Djokovic was given no assurances that a medical exemption would allow him into Australia, lawyers fighting to deport the tennis star have argued.
The court filing by lawyers for the Australian government also reveal Djokovic, 34, is unvaccinated.
Australia's Covid border rules ban non-double vaccinated foreigners from entering, unless they have a medical exemption from having the jabs.
Djokovic's legal team argue a recent infection gives him a valid exemption.
The Serbian tennis player flew into Melbourne last week, hoping to defend his Australian Open title.
But instead he has been held in an immigration detention centre as his lawyers prepare to appeal against a decision by Australia's federal government to cancel his visa.