Players who have not been vaccinated against Covid-19 are unlikely to be allowed into the country for the Australian Open, says the leader of the state in which the tournament is held.

The state has introduced a vaccination mandate for professional athletes.

"I don't think an unvaccinated tennis player is going to get a visa to come into this country," said Victoria Premier Daniel Andrews.

"If they did get a visa they'd probably have to quarantine for a couple of weeks.

"If I'm wrong I'm sure the federal government will let you know.

"[The virus] doesn't care what your tennis ranking is, or how many Grand Slams you've won. It's completely irrelevant. You need to be vaccinated to keep yourself safe and to keep others safe."

On Monday, reigning men's champion and world number one Novak Djokovic declined to reveal his vaccination status again and said he was unsure if he would defend his title in Melbourne, where he has triumphed nine times.

In an interview with Serbian publication Blic, the 20-time Grand Slam winner, said it was "a private matter and an inappropriate inquiry".

Australian prime minister Scott Morrison announced last week 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.

The 2021 tournament was pushed back by three weeks and players had to quarantine in a hotel for a fortnight on arrival in the country.

Tennis Australia insisted in May the tournament would proceed in January 2022 and in August, organisers said they hoped that players could have two weeks in a biosecure bubble rather than hotel quarantine.