There is considerable doubt as to whether January's Australian Open can be staged in Melbourne as planned.

The Tennis Channel reports that Victoria's government will not allow players to arrive in mid-December.

Tennis Australia had hoped they would be able to practise during the 14-day quarantine, before two weeks of action leading into the Australian Open.

Sources have since told BBC Sport that the state government's decision is unlikely to change.

Victoria premier Daniel Andrews said the government was still working with Tennis Australia on quarantine arrangements.

"We're confident that we'll finish up with an Australian Open," he said. "Whether [players] need to be here in December is the other issue.

"I don't know if that necessarily means there isn't an Australian Open."

However, players may be allowed into Australia at the end of December.

This would potentially give them enough time to be ready to start the Australian Open qualifying event, as scheduled, on Tuesday, 12 January.

But that assumes players will be able to practise during their quarantine - something which is likely but has not yet been signed off by the state authorities.

It may even still be possible for players to compete during the period of quarantine, as happened in New York in the run up to the US Open.

Another possibility is that the Australian Open may be pushed back by a week or two, to allow the warm-up events to go ahead as planned.

Tournament director Craig Tiley has openly discussed the potential delaying of the tournament in the past.

There would be repercussions for the events that normally take place in early February, but the first Grand Slam of the year is likely to be the priority.

The size of the draws could also be restricted, to reduce the number of people coming into the country.

There was no qualifying at September's US Open and there was no mixed doubles competition in either New York or at the French Open which followed.

Melbourne has reported no new cases of Covid-19 for 19 days, but a recent outbreak in Adelaide has alarmed those tasked with suppressing the virus.

The Association of Tennis Professionals (ATP) - the governing body of the men's tour - said it was working "as hard as possible" to deliver the calendar of events.

"In discussions with Tennis Australia over the past 24 hours, we have been informed there are some new challenges around the previously planned arrival dates for players and team members," the ATP said in a note to players.