The Federal Court has revealed the reasons why it rejected tennis star Novak Djokovic's challenge against the federal government's decision to cancel his visa.
In a unanimous decision, Chief Justice James Allsop, Justice Anthony Besanko and Justice David O'Callaghan said Immigration Minister Alex Hawke's decision to cancel Djokovic's visa was not irrational or illogical.
The three judges found it was not irrational for the Mr Hawke to be concerned that the support of anti-vaccination groups for Djokovic may encourage protests and further community transmission.
The judges said they did not consider the merits or wisdom of the minister's decision, only whether or not it was lawful.
The world number one men's tennis player was deported from Australia late on Sunday after he failed in a bid to have the visa cancellation overturned.
The full bench of the Federal Court unanimously agreed to dismiss Djokovic's application on Sunday before he was due to play in the Australian Open on Monday.
Djokovic could inspire 'anti-vaccination sentiment', court says
The reasons published online on Thursday afternoon make note of the tennis star's influence in the public sphere.
"This is not fanciful; it does not need evidence. It is the recognition of human behaviour from a modest familiarity with human experience.
"Even if Mr Djokovic did not win the Australian Open, the capacity of his presence in Australia playing tennis to encourage those who would emulate or wish to be like him is a rational foundation for the view that he might foster anti-vaccination sentiment."
The court outlined the central argument from Djokovic's legal team.
"The central proposition of Mr Djokovic's argument was that the Minister lacked any evidence and cited none that his presence may 'foster anti-vaccination sentiment'," the court said in its published reasons.
"However, it was open to infer that it was perceived by the public that Mr Djokovic was not in favour of vaccinations.
"It was known or at least perceived by the public that he had chosen not to be vaccinated.
The court also said the minister was not under any obligation to provide a statement of reasons in the case, but he did.
"They were evidently carefully drafted," the court said.
"There was a clear interrelationship among all parts of the Minister's reasons.
"The themes of encouragement and emulation of a sporting hero and icon run through the reasons for satisfaction as to health and good order and the public interest."
The court also said another person in the position of the minister might not have cancelled the visa.
"The Minister did. The complaints made in the proceeding do not find a conclusion that the satisfaction of the relevant factors and the exercise of discretion were reached and made unlawfully."
However, the court said there remained the question about to what extent "one can or should characterise lawful, even if robust, rallies and protests in the free expression of political or social views … as a threat to good order".
Decision 'justified' but questions remain about right to protest, expert says
Maria O'Sullivan, deputy director of the Castan Centre for Human Rights Law at Monash University, said the reasons were broadly unsurprising but important nevertheless.
"And one of the things the court said is that it's not necessary to have hard evidence about the effect an iconic tennis star like Mr Djokovic is going to have on the Australian community and in particularly anti-vax persons, you can just surmise that from common sense and general knowledge. So we didn't have to have hard evidence of that.
"So I think that's very justifiable, that finding."
Ms O'Sullivan said it did, however, raise an issue about the minister's powers.
She said the fact the minister was able to cancel someone's visa on the basis they encouraged protest could have troubling implications for democracy and freedom of speech.
"Academics and civil society in the past have regularly criticised the minister's powers," Ms O'Sullivan said.
"Secondly, what do we say now about the right to protest in Australia? Indeed, the full Federal Court in their reasons said that was an interesting question. They didn't settle that.
"That is definitely a future legal implication we need to address."
Ms O'Sullivan said it could mean other high-profile speakers could have their visas cancelled on similar grounds, for example, if a high-profile environmental advocate such as Greta Thunberg came to visit Australia.
"I think that's problematic because you are assuming in a way that lawful protests, particularly if you get a police permit, are a risk to social order, and that finding is problematic," she said.
