Novak Djokovic's deportation from Australia was "unjust" and the world number one will need time to move on from the saga, according to his long-time coach Marian Vajda.

The 20-time grand slam winner was denied the chance to claim a record-extending 10th crown at the Australian Open after having his visa cancelled on public health grounds.

Despite being unvaccinated against COVID-19, Djokovic had been given a medical exemption to travel to the country, only for that to be blocked by border officials.

He won his initial appeal to re-approve his visa, but immigration minister Alex Hawke used separate powers to revoke it again and a Federal Court upheld the decision.

The long-running case came to an end on Monday when Djokovic arrived back in Serbia, having reluctantly accepted the court's decision.

But Vajda, who has been part of Djokovic's coaching team for each of his grand slam titles, does not agree with the Australian government's handling of the situation.

"I still don't understand why they did it to him," Vajda told Slovakian outlet Aktuality. 

"It was an unhealthy and unjust decision, based on the assumption that Djokovic could do or influence something that had not yet happened.

"I can't imagine how he handled it. It must have been a huge suffering.

"He humbly endured all measures. But what they did to him must mark him. It is clear that it hit him mentally. 

"It will hurt him for a long time and it will be difficult to get it out of his head. However, I know him very well. Novak is strong, resolute and has not yet said his last word in tennis."

Men's grand slam winners - Djokovic, Federer, Nadal

In a further blow for Djokovic, who has stood firm on his refusal to be vaccinated, it emerged this week that the Serbian may also miss the France Open later this year.

That is after stringent laws were passed in France ahead of May's tournament at Roland Garros that will make proof of vaccination status mandatory to enter sporting arenas.

"I don't understand this," Vajda added. "Why is it important for them to announce this now about the tournaments that will take place in May?

"The world doesn't even know what will happen to the pandemic in a month.

"I do not want to underestimate the whole situation. It is serious in the world. But what is the purpose of discussing it now in January? Is it still about sport?"