Two members of the Haas Formula One team and one from McLaren were quarantined in Melbourne on Wednesday as a precaution amid coronavirus fears ahead of Sunday's season-opening Australian Grand Prix.
"Two members showed some cold-like symptoms this morning. With the guidelines we've followed, they have been tested (for coronavirus)," a Haas spokesman told Reuters at Albert Park.
"As a result of being tested they have to go back into the hotel for isolation while we await the results."
McLaren said one team member had self-isolated in the team hotel as a precaution for showing "coronavirus-like symptoms".
"We expect to receive the results overnight. The team is operating as per our normal schedule," a spokeswoman said.
Reuters has sought comment from race organisers.
Both Haas and McLaren are Britain-based, while Haas has close ties with Italy-based Ferrari, which supplies their power units.
Italian authorities have been struggling to contain a major outbreak of the coronavirus.
More than 119,100 people have been infected by the coronavirus across the world and 4,298 have died, according to a Reuters tally.
Australia extended its travel ban to Italy on Wednesday after the southern European nation expanded a lockdown to cover the entire country to contain the spread of the virus.
Australia has already barred entry to those arriving directly from mainland China, South Korea and Iran, except for its citizens and permanent residents.
A spokeswoman for Ferrari said none of its team members had been quarantined or tested.
"All are present and accounted for," she said.
Formula One organisers have already postponed the Chinese race scheduled in April, while the Bahrain Grand Prix will go ahead without spectators on March 22.
Australian Grand Prix Corporation chief executive Andrew Westacott had said on Monday that Albert Park was ready to welcome thousands of motorsport fans and there was "no chance" of a spectator ban.
More than 300,000 people attended race week last year, according to organisers' estimates,
With a surge in local cases in recent days and confirmed community transmission in Melbourne, organisers have been under fire from some media pundits for insisting the race will go ahead without restrictions.
The words "STOP F1" were written in the skies above Sydney on Wednesday but it was unclear who was responsible for the sky-writing.