Volpato was pulled over by police on Sydney's Anzac Bridge on July 24 and returned a positive roadside reading for cocaine.
The 22-year-old then underwent independent testing at a private clinic, where it was claimed he returned a negative reading.
But Volpato was then sent for a secondary oral fluid test by police, which again confirmed a positive result for cocaine.
"On Tuesday 1 September 2026, a 22-year-old man was issued a Traffic Infringement Notice for drive motor vehicle with illicit drug present in oral fluid," NSW Police told AAP.
Volpato, who will face no further action, was handed a $722 fine as a result of the second positive test.
The Sassuolo forward had been pulled over by police after driving at 109km/h in a 60km/h zone.
The Sydney-born youngster was a late inclusion for the Socceroos' World Cup campaign after switching his international allegiance from Italy to Australia on the eve of the tournament.
Volpato maintained his innocence over the failed drugs test when he spoke to Football Australia (FA) staff, insisting that he never knowingly ingested the substance.
He also undertook a test when he returned to Italy which was negative, his club side Sassuolo said.
In a statement provided to AAP, FA said: "Football Australia has been made aware of information concerning a reported secondary oral test result relating to one of our players. We are currently seeking independent verification.
"The matter is being managed in accordance with Football Australia's established protocols. To protect the integrity of this process and ensure procedural fairness, we will not comment further."
But the positive reading on Volpato's secondary police test could have major ramifications for his availability heading into January's Asian Cup.
Sources have told AAP that Volpato could be hauled before FA's disciplinary and ethics committee, where the sport's governing body has the power to suspend him from national team action.
The closest comparable case to Volpato's is that of A-League Women goalkeeper Teresa Morrissey, who tested positive for cannabis while driving.
Morrissey claimed the cannabis had been used for medicinal purposes, but was still slugged with a three-game ban by FA last year, which the goalkeeper's legal team had argued was disproportionate with her public profile.
Volpato's off-field indiscretion attracted headlines in Australia and in Italy, where he plays in Serie A.
He has played three games for Sassuolo this season, but failed to finish their last game against Bologna because of a suspected hamstring injury.
Socceroos coach Tony Popovic wouldn't be drawn on whether he would pick Volpato for this month's friendlies with Brazil when he spoke at a press conference in Sydney on Tuesday.
"I don't know exactly the details of what happened and it would be wrong to speculate on what happened," Popovic told reporters.
"These young men, things happen and you can get caught for something we have to look into.
"There is a process that's playing out at the moment and we need to follow that process.
"When that is played out as it should, then (only then) I can really comment on that."
