Djokovic had initially been granted a medical exemption from the country's COVID-19 vaccination requirements.
But Thursday he was issued a letter by the Australian government saying his visa had been denied and he would be removed from the country, according to a source close to the tournament.
Australian Health Minister, Greg Hunt:
“There was an exemption that had been provided through the Victorian Government process, clearly that did not pass the standards of proof that were required by the Australian Border Force. Yes it's tough, but it's fair and it's equitable and it's one rule for all under this Australian government."
In a dramatic series of events through the Melbourne night, Djokovic touched down at the airport Wednesday about 11:30 p.m. local time after a 14-hour flight from Dubai, but was ushered into an isolation room under police guard when Australian officials said that his visa did not allow for medical exemptions.
Djokovic, a source tells Reuters, was filing an injunction to prevent his deportation.
Serbian president Aleksandar Vucic posted on Instagram in part quote:
"I told our Novak that the whole of Serbia is with him and that our bodies are doing everything to see that the harassment of the world's best tennis player is brought to an end immediately.
Serbian media reported that Vucic had summoned the Australian ambassador in Belgrade and demanded that they immediately release Djokovic to play.
Australian Prime Minister Scott Morrison has faced an enormous backlash over his government's decision to grant Djokovic a medical exemption to play at the Open.
Djokovic - the world number one male tennis player, has never publicly revealed his vaccination status.