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 organizer 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 preseason 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 preseason training routine."

Federer has won the Australian Open six times. But after losing in the semifinals to Novak Djokovic, missed the rest of the coronavirus-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 to 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.