Federal Immigration Minister Alex Hawke has cancelled Novak Djokovic's visa, but there is still a chance he could play in the Australian Open.
Djokovic has already been named the top seed in the tournament, which starts on Monday.
While the government now intends to deport him, Djokovic's legal team is expected to appeal Hawke's decision.
"They will be seeking two things, I think," former deputy secretary of the Immigration Department Abul Rizvi said on Friday evening, speaking on Channel 10.
"One, to argue the matter on legal grounds. Secondly, to ask the judge for permission for Mr Djokovic to be released on a bridging visa to enable him to participate in the Australian Open.
"That is a decision the judge would need to make over the weekend."
There's an additional complicating factor, however. Such a bridging visa would typically not allow the recipient to work.
"Playing tennis, some people may not regard it as work, but it is Mr Djokovic's job," Mr Rizvi said.
"(The judge) would need to consider those issues as well, whether he gets work rights with the bridging visa. That is an issue the judge will consider.
"If he thinks there is merit in Mr Djokovic's argument, it makes sense to release him on a bridging visa while the appeal is considered."
In a separate appearance on ABC TV, Mr Rizvi said Djokovic could be stuck in detention, "if it is the case that the judge accepts there are strong public interest grounds" to keep him there.
In his statement announcing the decision this evening, Mr Hawke said Djokovic's visa was being rescinded on "health" and "public order" grounds.
"Today I exercised my power under section 133C(3) of the Migration Act to cancel the visa held by Mr Novak Djokovic on health and good order grounds, on the basis that it was in the public interest to do so," Hawke said.
"This decision followed orders by the Federal Circuit and Family Court on January 10, quashing a prior cancellation decision on procedural fairness grounds.
"In making this decision, I carefully considered information provided to me by the Department of Home Affairs, the Australian Border Force and Mr Djokovic.
"The Morrison government is firmly committed to protecting Australia's borders, particularly in relation to the Covid pandemic.
"I thank the officers of the Department of Home Affairs and the Australian Border Force."
The Victorian government issued a statement of its own, saying the visa issue "remains between the federal government and Novak Djokovic".
It said it would be inappropriate to comment further, given Djokovic's team had signalled its intention to challenge the decision in court.
Prime Minister Scott Morrison, meanwhile, stressed that the Covid pandemic had been "incredibly difficult" for every Australian but people had stuck together.
"Australians have made many sacrifices during this pandemic, and they rightly expect the result of those sacrifices to be protected. This is what the Minister is doing in taking this action today," said Morrison.
"Our strong border protection policies have kept Australians safe, prior to Covid and now during the pandemic.
"Due to the expected ongoing legal proceedings, I will not be providing any further comment."
Djokovic, who is unvaccinated, received a medical exemption to compete in the year's first grand slam but when he touched down in Melbourne last week, was told by the Australian Border Force he had insufficient evidence to prove his exemption was justified.
The nine-time Australian Open champion was kept in a Melbourne hotel until the end of Monday's hearing, when he was released from detention.
Djokovic's exemption was based on his and Tennis Australia's belief that having contracted Covid-19 in the past six months was a valid reason to not be vaccinated.