All players and staff at this month's tournament must be vaccinated or have an exemption granted by an expert independent panel.
Defending champion Djokovic - a nine-time winner - has not spoken publicly about his vaccination status.
Jamie Murray questioned the reasoning behind the decision to grant the Serb an exemption, with the Scot stating: "I mean, I don't know what to say about that really... I think if it was me that wasn't vaccinated, I wouldn't be getting an exemption.”
Tournament director Craig Tiley said 26 unvaccinated players applied for exemption, with only a "handful" granted.
"We made it extra difficult for anyone applying for an application to ensure it was the right process and to make sure the medical experts deal with it independently," Tiley told Channel Nine's The Today Show.
"There has been no special favour or special opportunity granted to Novak Djokovic or any tennis player.
"There's been a process that goes above and beyond the normal process for everyone."
The Australian Open is scheduled to begin on January 17 in Melbourne.
Reasons for Djokovic being permitted to compete will remain private, according to Tiley.
Criteria listed by the Australian Technical Advisory Group as permissible reasons for a medical exemption range from acute major medical conditions to any serious adverse event attributed to a previous dose of Covid-19 vaccine.
A possible explanation is that Djokovic has contracted coronavirus for a second time at some point in the past six months, having previously caught it during his much-criticised Adria Tour event in Belgrade in 2020.
That would negate the need for vaccination, according to rules published last year by one of two independent medical panels involved in the decision.
The build-up to the season's first grand slam has been dominated by whether Djokovic would compete.
Speculation was heightened after he pulled out of the Serbia team competing at the ATP Cup in Sydney without explanation.
On Tuesday, the 34-year-old Serbian posted on Instagram that he was "heading down under with an exemption permission".
The news was later confirmed in a statement from the Australian Open.
The tournament provides Djokovic with another chance to move clear of rivals Roger Federer and Rafael Nadal, with the three having each won 20 grand slam titles.
He was challenging for the calendar year grand slam in 2021 but fell short in the US Open final by losing to Daniil Medvedev, the man he beat in last year's Australian Open final.