Novak Djokovic has left Australia but questions remain over the rules that shut him out

The Australian Open tennis tournament began on Monday without the world's top men's player, who departed the night before in a cloud of government suspicion that he could incite the country's anti-vaxxers.

Novak Djokovic arrived back in Belgrade, Serbia after losing a court challenge against the Australian government's decision to cancel his visa on public health and order grounds.

Under Australian law, Djokovic can be banned from the country for three years, though Home Affairs Minister Karen Andrews hasn't ruled out an exemption. "Any application will be reviewed on its merits," she said.

Australia is not alone in banning entry to unvaccinated travellers who are unable to prove why they can't be inoculated, but it's the first to take on such a high-profile target.

Prime Minister Scott Morrison said the government was protecting the sacrifices Australians made during the pandemic. But he was also partly protecting his own prospects ahead of a forthcoming federal election.

The Australian government has promoted vaccination as a way out of the pandemic -- and more than 92 per cent of people over the age of 16 are fully vaccinated against COVID-19.

After Sunday's hearing the government cast Djokovic's ejection as a triumph for ordinary Australians over non-citizens who try to flout the rules.

"The idea that someone could come and not follow those rules was just not on," Morrison told local radio Monday.

But some lawyers say the government's decision to bar entry to someone who they fear might pose a risk sets a "dangerous precedent" by banning people because of their past comments or an assumption that they plan to cause trouble.

Meanwhile, refugee advocates fear Djokovic's departure will take the attention away from the people still living with consequences of the government's immigration policies -- the refugees inside the detention facility where he stayed.

A SUPERSTAR IN DETENTION

Australia was among the first countries to shut its borders in March 2020 as COVID-19 spread.

Many Australian citizens were locked out by flight caps on passengers, as a procession of celebrities somehow found a way in. As the country started reopening in December, new rules were imposed requiring all new arrivals to be double vaccinated -- unless they had a valid medical exemption.

So when Djokovic landed in Melbourne on January 5 and claimed he couldn't be vaccinated due to a past COVID-19 infection, Australian Border Force officers were quick to act. Perhaps too quick, because days later a judge ruled the Serb hadn't been given enough time to consult his lawyers and ordered his visa to be reinstated.

Under Australian law, medical exemptions are only given to people who can prove they've suffered anaphylaxis after a previous dose, or any component of a vaccine, or are significantly immunocompromised. Djovokic didn't fit either category.

On Monday, after being freed from immigration detention, Djokovic started training for a shot at his 21st grand slam title. But his freedom was curtailed four days later when Immigration Minister Alex Hawke revoked his visa, putting the player back in detention.

Ultimately Djokovic's case had nothing to do with whether he satisfied Australia's COVID-19 entry requirements. Nor did it seem to be a problem that his travel declaration misstated his movements in the 14 days before his arrival in Australia.

Instead the minister found he posed a risk to public health and order because, as a celebrity sportsman who had previously expressed opposition to vaccination, he could be seen as an "icon" for anti-vaxxers.

Australia is home to a small but determined anti-vaccine movement, which last year held protests across the country to demonstrate against the government's vaccine program and pandemic measures.

But Greg Barns, a barrister and spokesperson for the Australian Lawyers Alliance, said the decision sets a "dangerous precedent" because the purpose of Djokovic's visit was to play tennis -- not to spread his views on COVID-19 vaccines.

"Effectively, what the government is saying is that if you're a high-profile person, and you have particular views with which the government disagrees ... then the government reserves the right to either cancel your visa while you're in the country or not grant a visa."

TOUGH ON BORDERS

When Djokovic's visa was cancelled on January 6 he found himself in unfamiliar surrounds -- the first floor of Park Hotel, an immigration detention facility in central Melbourne.

Until the arrival of the world No.1 at the hotel, the plight of the men inside had generated little debate in the wider Australian public.

But Djokovic's visa issue focused attention on Australia's immigration policy -- the same policy that's kept some refugees and asylum seekers detained indefinitely.

"I am worried that the spotlight will fade on the refugees and asylum seekers now that Djokovic has gone," said Elaine Pearson, the Australia director of Human Rights Watch (HRW).

The men in Park Hotel didn't have their visas cancelled -- they were never given a right to stay in Australia under the country's policy of not allowing refugees who arrived by boat after July 2013 to ever settle in the country. Most were found to be refugees in need of protection.

But in a radio interview on Monday morning, it seemed the Prime Minister had already forgotten, or didn't know why they were there.

"I mean, it's not clear that to my information that someone in that case is actually a refugee," Morrison said, when asked about the men in Park Hotel. "They may have sought asylum and been found not to be a refugee and have chosen not to return."

Pearson said Morrison's comments were a "blatant lie."

"(He) should know better than anyone," she said. "He's a former immigration minister."

The Asylum Seeker Resource Centre (ASRC) meanwhile said Morrison's statement was "misleading and false."

For more than a week, refugees detained inside the building have been speaking to international media about their plight, particularly Mehdi, an Iranian refugee held for more than eight years who turned 24 during Djokovic's stay.

"If I'm not a refugee, why would I endure such a difficult time as a child if I have the option to go back to where I came from? Even then, I'm not safe in detention either," he tweeted Monday.

The Australian government says its policies are designed to save lives at sea by stopping traffickers from undertaking the dangerous journey with desperate human cargo.

But it's not just refugees who lawyers worry are at risk. Other permanent and temporary visa holders can have their visa cancelled and are subject to mandatory detention before being removed. For stateless people with nowhere to go, it can mean indefinite detention.

According to government figures, 946 visas were cancelled in the 2020-21 financial year, under provisions that allow the government to cancel visas on character grounds -- namely if the visa holder has committed a crime.

Most people removed during that period were from New Zealand and the United Kingdom after convictions for drug offences.

But visas can also be cancelled if the government suspects that a person could engage in criminal conduct if allowed to enter. In Djokovic's case, the government thought his mere presence could encourage anti-vax protests.

The ASRC, the Visa Cancellation Working Group, and the Refugee Advice and Casework Service are calling for an urgent inquiry into visa cancellations -- saying the laws make it too easy for government ministers to intervene and don't give people enough power to challenge the decision in court.

"There are a whole range of different powers under which the government can cancel people's visas," said Graydon. "And the lack of consistency in exercising those powers is against the public interest that these powers are supposed to be about serving."

"Even if people are successful in having their visas reinstated, it can then be undone through ministerial discretion," she said. "The laws have been structured to amplify executive power at the expense of parliamentary scrutiny and judicial scrutiny of decision making."