Reports have emerged that Novak Djokovic has had a dramatic change of heart around his COVID vaccination status, with claims the famously unvaccinated tennis star will get the jab.

The reports come from the author of Djokovic’s upcoming biography, Daniel Muksch.

He has suggested the world No.1’s enforced spell on the sidelines for the Australian Open – as he watched long-time rival Rafael Nadal win a historic 21st grand slam – has convinced the Serbian star to change his tune.

It came as Serbian authorities doubled down on claims by the 34-year-old that he had tested positive to the virus, for at least the second time, in December.

Djokovic infamously flew into Melbourne for the year’s opening grand slam early in January to uproar from Australian media, politicians and the public. He used his recent infection to claim a medical exemption from Australia’s strict vaccination requirements.

But Djokovic’s plans to compete unvaccinated took a turn when he was forced into hotel quarantine on arrival because of issues with his visa, including his lack of vaccination. The visa was later cancelled by the federal government, and Djokovic failed in a high-stakes bid to have reinstated in the Federal Court.

The federal government said it feared Djokovic’s presence in Australia could stir up anti-vaccination sentiments.

He was denied the chance to defend his Australian title and deported on January 16, on the eve of the tournament.

Nadal went on to take a record 21st men’s grand slam title with victory at the Australian Open – leaving the Serb and his other big rival Roger Federer both trailing on 20 major titles.

“From what I have heard from those around him, I think he is getting vaccinated,” Muksch, told Austria’s Servus TV on Thursday (Australian time).

“Maybe the final in Melbourne also contributed to that. Rafael Nadal’s 21[st grand slam win] is driving him, no question.”

Asked about the reports on Thursday, federal Health Minister Greg Hunt said he hadn’t heard the report but would be “delighted” if Djokovic changed his anti-vaccine stance.

“I’m happy for anybody anywhere to be vaccinated and if in some small way as a country we have encouraged Novak or any other individual to do that then that’s great,” he told Seven’s Sunrise program.

“But you know what’s much more important? I think that will encourage more people who have been hesitant to be vaccinated and that would be the real win out of this.”

The report came days after Djokovic’ heartfelt message to Nadal after his Melbourne Park finals triumph over Daniil Medvedev. The Serb also congratulated Australia’s Ash Barty for her title win over Danielle Collins.

Muksch is the author of Djokovic’s biography, entitled A Lifetime at War. It is scheduled to be published later this year.

Elsewhere, Serbia’s state prosecutors have rejected reports that Djokovic used a fake positive test for COVID as the basis for his visa exemption claim when he tried to enter Australia and defend his Open title.

The country’s prosecution office said in a statement on Wednesday (local time) that it had received a request for criminal proceedings against unnamed individuals who allegedly forged two PCR certificates, later used by the star player to apply for a medical exemption.

“The prosecution acted according to the regulations, checks were performed, and it was determined that Novak Djokovic was tested several times and that the certificates on the test results from December 16, 2021, and December 22, 2021, are valid,” the statement said.

The BBC and German media outlet Der Spiegel had earlier reported discrepancies in serial numbers on tests administered by Serbian authorities to the top-ranked Djokovic ahead of his trip to Australia, suggesting possible irregularities in the way they were issued.

Djokovic’s media team and Serbian health authorities did not respond to requests for comment. Senior Serbian health officials have previously said that Djokovic’s test was valid.

The world No.1 is adored in his native Serbia. Since he returned home, he has been seen visiting churches and attending liturgies in Serbia and neighbouring Montenegro.

On Thursday, he will visit Serbia’s populist President Aleksandar Vucic, who was vocal in denouncing the Australian authorities for deporting the tennis star.

– with AAP