Australia cancelled Novak Djokovic’s visa for a second time on Friday in a sensational new attempt to deport the unvaccinated tennis superstar.

Djokovic has also been ordered detained following the outcome of a new appeal, in a dramatic setback to the tennis world number one's goal of winning a record 21st Grand Slam.

As time slips away before the Australian Open starts Monday, the nine-time title holder heard in an emergency hearing on Friday evening that he will be in immigration detention from Saturday morning -- not on the Melbourne Park tennis courts.

The megastar's bid to avoid deportation will be heard by Australia's Federal Court at 10.15am Saturday (6.15am Thailand time).

The government has agreed not to deport the 34-year-old Serbian tennis ace until the hearing is over, barrister Stephen Lloyd told an emergency late-night session of the federal circuit court.

But Djokovic is expected to report to government offices at 8am Saturday to be placed in detention.

He would be allowed out of detention to follow online court hearing at his solicitors' offices, but only under the supervision of Australian Border Force officers, the barrister said.

It is unclear clear if Djokovic will choose to stay and fight the case if he believes he is unable to compete in the Australian Open.

The country’s conservative government, defeated once in the courts, invoked extraordinary executive powers to again rip up the 34-year-old Serbian’s visa on public interest grounds.

Djokovic, an avowed Covid-19 vaccine sceptic, is the tournament’s top seed and had been practising on the Melbourne Park courts just hours before Immigration Minister Alex Hawke’s bombshell decision was announced.

The government is “firmly committed to protecting Australia’s borders, particularly in relation to the Covid-19 pandemic”, Hawke said in a statement.

He cited “health and good order grounds” for the decision and said “it was in the public interest to do so”.

Prime Minister Scott Morrison backed the decision: “Australians have made many sacrifices during this pandemic, and they rightly expect the result of those sacrifices to be protected.”

The visa cancellation effectively means the world’s number one tennis player would be barred from obtaining a new Australian visa for three years, except under exceptional circumstances.

Djokovic’s lawyer Nick Wood immediately requested an injunction against his client's removal. He appealed unsuccessfully for him to be allowed to remain out of immigration detention as the case proceeds.

“We are very concerned about time,” Wood said, arguing that the government’s decision was marked by “irrationality".

‘All fools’

In Belgrade, Djokovic’s compatriots reacted with shock to the news.

“To say that a high-level sportsman like Novak is a danger to the health of Australians is just absurd, it’s a scandal,” said 28-year-old local government employee Petar Stojanovic.

The megastar flew into Melbourne airport on Jan 5 claiming a vaccine exemption because of a positive PCR test result on Dec 16.

Border agents rejected his exemption, revoked his visa and placed him in a notorious Melbourne detention centre where he spent four nights.

The Australian government insists a recent infection does not qualify as a vaccine exemption for foreign nationals trying to enter the country.

Djokovic’s top-flight legal team overturned the visa decision in the federal circuit court on Monday because border officials at the airport had failed to give him the agreed time to respond.

Djokovic’s vaccine waiver provoked outrage among many Australians who have endured nearly two years of some of the toughest coronavirus restrictions in the world.

Some tennis players say Djokovic should now be allowed to play, but not all have been supportive.

World number four Stefanos Tsitsipas criticised his behaviour.

“For sure he has been playing by his own rules,” Tsitsipas said in an interview with the Indian broadcaster WION.

Nearly everyone in the Australian Open had been vaccinated, Tsitsipas said. But others “chose to follow their own way which kind of makes the majority look like they’re all fools”.

‘Error of judgement’

On Wednesday, Djokovic described reports about post-infection outings without a mask in Serbia as “misinformation”.

On the day of his claimed positive test in Serbia, he attended a ceremony to honour him with stamps bearing his image. The following day he attended a youth tennis event. He appeared at both apparently without a mask.

Djokovic said in an Instagram post that he only received the PCR test result after going to the children’s tennis event on Dec 17.

But he admitted that he also went ahead with an interview with French sports outlet L’Equipe on Dec 18.

“On reflection, this was an error of judgement and I accept that I should have rescheduled this commitment,” Djokovic said.

The journalist who carried out the L’Equipe interview, Franck Ramella, said he had been unaware at the time of the interview that Djokovic was Covid-positive.

The tennis star also admitted to a mistake on his Australian travel declaration, in which a box was ticked indicating that he had not, or would not, travel in the 14 days before flying to Melbourne.

In fact, social media posts and reports show he flew from Serbia to Spain during that period.

Djokovic blamed his support team for this. “My agent sincerely apologises for the administrative mistake in ticking the incorrect box,” he said.

As Covid-related hospitalisations rise in Melbourne, the Victorian state government said Thursday it would cap capacity at the Australian Open at 50%.