Novak Djokovic has expressed doubts over playing in the Australian Open in January after officials said unvaccinated players are unlikely to be allowed to enter the country for the event.
The 34-year-old, a record nine-time champion in Melbourne, refused to reveal his vaccination status but implied the announcement made it less likely he would compete.
Djokovic told Serbia's Blic: "Things beings as they are, I still don't know if I will go to Melbourne.
"I will not reveal my status whether I have been vaccinated or not, it is a private matter and an inappropriate inquiry.
"People go too far these days in taking the liberty to ask questions and judge a person. Whatever you say 'Yes, no, maybe, I am thinking about it', they will take advantage."
The state of Victoria, which is scheduled to host the first major of 2022 in January, has introduced a vaccination mandate for professional athletes as it battles a resurgence of Covid-19 cases.
Victorian premier Daniel Andrews on Tuesday told reporters: "I don't think an unvaccinated tennis player is going to get a visa to come into this country and if they did get a visa they'd probably have to quarantine for a couple of weeks."
In May Djokovic said he hoped vaccination would not be made mandatory for players on the tour, insisting it ought to come down to freedom of choice.
Djokovic was forced to apologise after staging a charity event in Serbia in 2020 with no social-distancing measures in place, after which a number of players, including Djokovic himself, tested positive for the virus.
At this year's Australian Open, his demands for greater freedom for players undergoing mandatory quarantine prior to the tournament in Melbourne fell on deaf ears, with officials maintaining he would get "no special treatment".
Australian prime minister Scott Morrison announced on Friday that international travel to and from the country would resume from 1 November for citizens and permanent residents, but emphasised "no decision to allow other visa-holders" had yet been made.
Tournament organisers had to overcome many obstacles to hold the event this year, with the start date pushed back three weeks and players forced to quarantine for a fortnight on arrival in the country.
Tennis Australia insisted in May that the tournament would proceed in January 2022.