Australia forward Cristian Volpato tested positive for cocaine during a roadside test after being stopped for speeding in Sydney on Friday, local media reported.
New South Wales Police said a 22-year-old man was stopped for speeding twice and drug-tested after driving a BMW at 109 kph (68 mph) in a 60 km/h zone on Anzac Bridge at around 1:10 a.m. on Friday.
The man was issued an infringement notice for speeding and had his international driver's license suspended for six months. Police were continuing inquiries.
Multiple Australian media outlets reported Volpato as the driver, citing the NSW Police statement.
Governing body Football Australia (FA) said it was aware of the allegations against one of its players.
"We have been in contact with the player and continue to monitor the matter and support the player throughout this process," an FA spokesperson said in a statement, without naming the player.
Australia's players union, Professional Footballers Australia, said in a statement: "The PFA is aware of reports concerning Cristian Volpato and will ensure he is supported."
Volpato plays in Italy's Serie A for Sassuolo and represented Italy at junior levels before switching allegiance to Australia ahead of this year's World Cup.