In short:

Socceroos star Cristian Volpato has allegedly tested positive for cocaine while driving in Sydney.

The 22-year-old was stopped in a BMW coupe about 1am today, allegedly travelling 109 kilometres an hour on the Anzac Bridge, a 60km/h zone.

Football Australia said the association was aware of the allegations. 

Socceroos star Cristian Volpato has allegedly tested positive for cocaine while driving in Sydney.

The 22-year-old was stopped in a BMW Coupe about 1am today, allegedly travelling 109 kilometres an hour on the Anzac Bridge, a 60km/h zone.

He was subjected to a roadside drug test, which allegedly returned a positive result for cocaine.

Mr Volpato was issued with a speeding fine and has had his international driver's licence suspended for six months, meaning he cannot drive in New South Wales.

A secondary sample of oral fluid was taken for further analysis, with police confirming inquiries were continuing.

Police will allege they stopped Mr Volpato a few hours earlier, about 11pm yesterday, in the same area where he was also speeding.

He was subjected to a roadside alcohol breath test, which returned a negative result.

In a statement, Football Australia said the association "was aware of the allegations involving one of our players."

"We have been in contact with the player and continue to monitor the matter and support the player throughout this process," a Football Australia spokesperson said.

Sources say the 22-year-old has denied allegations and underwent a voluntary independent test, which was submitted to Football Australia and returned a negative result earlier today.

Mr Volpato made headlines when he switched allegiance from Italy to Australia in the World Cup this year.

Football Australia has a strict drug regulation policy managed through Sport Integrity Australia.

Players and officials who test positive to prohibited substances without a valid therapeutic use exemption can be suspended for up to four years.

That can be reduced to three months if the use was out of competition and not performance-related.