Pakula said on Wednesday the Open was very keen to have the nine-time champion back to defend his title but the safety of the community came first.

With the major in January requiring all attendees to be fully vaccinated Djokovic's father Srdjan said the rules were tantamount to "blackmail".

The Serbian star has refused to reveal his vaccination status, saying it's a personal matter.

But his father said the 34-year-old "probably" wouldn't attend if there was no change in the strict conditions of entry.

"Of course he would want to go with all his heart," Srdjan told Serbia's Prda TV.

"But I really don't know if that will happen. Probably not under these conditions, with this blackmail and when it's done that way."

Pakula initially responded on social media denying the vaccination mandate was blackmail and doubled-down on his position on Wednesday.

"If you're a visiting international tennis player or a visiting sportsman of any kind it's about your responsibility to the community that you are being welcomed into," Pakula said.

"And that's why we are asking those international tennis stars to follow the same requirements as Victorians are.

"It's not about blackmail it's about making sure the Victorian community is protected.

"I want to make it clear that I really hope that Novak Djokovic gets vaccinated and plays in the Australian Open.

"But if he chooses not to, that's a matter for him."

Djokovic's position in the ongoing saga is expected to become clearer in the next fortnight when entries into the Open close.

The Open, starting on January 17, is now less than seven weeks away.

Australian Associated Press