All the world's top players, including 20-time Grand Slam champion Roger Federer, are expected to be in Melbourne for the coronavirus-disrupted Australian Open, tournament organiser Craig Tiley said.

The opening Grand Slam of the year, in front of at least 50 percent of normal crowds, has been pushed back three weeks until February 8 with all players to undergo a mandatory 14-day quarantine on arrival.

The delay could be pivotal for Federer, who admitted last week he was in a "race against time" to be fit as his recovery from two rounds of knee surgery takes longer than expected.

Tiley said he had been in touch with the 39-year-old and he was going through his normal pre-season training routine in Dubai.

-Every player, including Roger, has made a commitment to travel to Melbourne to play- he said after confirming the new start date on Saturday.

-We have been in touch with him and his team and it's been three days now, he's hit for the first time in Dubai. He's in his normal pre-season training routine. -

-He did say to us that February 8 was a more suitable date for him in terms of preparing for the Australian Open- Tiley added. -But a lot will depend on how he responds to his surgery in the next two to three weeks of training."

Federer has won the Australian Open six times. But after losing in the semi-finals to Novak Djokovic, missed the rest of the Covid-interrupted 2020 season following surgery and could only watch as Rafael Nadal matched his record 20 Grand Slam titles with a 13th victory at the French Open.

The men's and women's qualifiers will be held in Doha and Dubai respectively from January 10-13, with players arriving in Melbourne from January 15 on special charter flights for their quarantine.

Tiley said they would constantly be tested for Covid-19 but allowed to train for five hours a day in a bio-secure bubble, although with just one other player.

They will be shuttled between designated hotels and Melbourne Park, where the tournament is held and if anyone tests positive, they will need to isolate in their room.

-If there are any breaches (of quarantine) the player will be immediately removed from the country as well as being fined- Tiley warned.

A slimmed-down, 12-team ATP Cup, the relocated Adelaide International, and a ATP 250 tournament will all be played in Melbourne once players are out of isolation.

Two WTA 500 tournaments are also planned to be held concurrently at Melbourne Park on January 31-February 7.

Melbourne only emerged from a months-long lockdown in October following a second wave of Covid-19, complicating planning for the Grand Slam and how to allow so many players and support staff to enter the country safely.

Australia has largely contained the coronavirus although a new outbreak in Sydney over recent days has sparked fresh restrictions in parts of the city and even state border closures.