The state of Victoria, where the Grand Slam event takes place in Melbourne, has introduced a vaccine mandate for professional athletes, although authorities have not yet clarified what the requirement will be for those coming from abroad.
"Things beings as they are, I still don't know if I will go to Melbourne, Djokovic said.
"I will not reveal my status whether I have been vaccinated or not, it is a private matter and an inappropriate inquiry.
Djokovic has won the season's opening Grand Slam a record nine times, including the last three editions.
The 34-year-old last competed at the U.S. Open, where his bid to complete the calendar slam -- winning all four majors in the same year -- was ended by Russian Daniil Medvedev in the final.