Coronavirus: Pandemic hits F1 paddock on the eve of Melbourne Grand Prix

More Formula One team staff have been quarantined and tested for coronavirus, amid fresh uncertainty over the Melbourne Grand Prix.

The Haas team say two more of their crew have been isolated and tested for the virus on Thursday.

Haas now have four staff and the McLaren team one team member in quarantine in Melbourne, awaiting test results before the Grand Prix, due to start with practice sessions on Friday.

Haas team principal Guenther Steiner says the two latest quarantined staff had reported feeling unwell.

"It's four in total - one engineer and I think three mechanics," he told reporters at the Albert Park circuit on Thursday.

"We should collect the results in the afternoon.

"At the moment, we can cope... the most impact for me is that I hope that they are well, and this afternoon, that they just have a cold, and can come back and work tomorrow."

On Wednesday, the McLaren team were uncertain when they would receive results from tests on a staffer.

The latest possible cases came after Victoria's chief health officer Brett Sutton warned that positive tests at Albert Park could stop the race being held.

"If [the tests] turn up positive, we need to consider what it means for their close contacts and if they have a number of close contacts across a number of crews, then those individuals need to be quarantined," Sutton told Melbourne radio station 3AW.

"If that effectively shuts down the race, then so be it. We'll make that call."

The Australian Grand Prix Corporation did not immediately comment on the tests or the viability of holding the race.

Despite coronavirus concerns, spectators turned up to Albert Park on Thursday to watch practice and qualifying for lower-profile racing classes.

The Chinese Grand Prix, scheduled for April, has been postponed, while the Bahrain GP - the second stop on the F1 calendar - has banned fans from attending the March 22 race.

But Sutton said there was little point in banning spectators at the Melbourne race.

"I don't think crowds are the issue here," he said. "I think the segregation of [F1] crews from each other and also the crowd is really important, but crowd gathering is like any other mass gathering.

"Three hundred thousand come every day to the city to work - that's a mass gathering. Public transport is a mass gathering every day."