Supercars chief executive Sean Seamer has lashed out at drivers comparing Scott McLaughlin to disgraced cyclist Lance Armstrong.
The Herald Sun obtained an email Seamer sent out to all the Supercars teams, warning that "sledges and abuse" over McLaughlin's Bathurst victory are bringing the "sport into disrepute".
Seamer singled out stinging comments made on social media by Scott Pye that likened McLaughlin to drug cheat Armstrong.
McLaughlin has been continually sledged by rivals, who have questioned the legitimacy of the Kiwi's Ford Mustang and suggested his Bathurst victory was more about the car than driver.
The 26-year-old was later penalised for an engine breach, which led Pye to compare him to Armstong, who was stripped of his Tour de France titles in 2012, after he confessed to doping during his career.
"I was disappointed to read the recent public social media comments and associated media coverage regarding various sledges and abuse by drivers and team representatives," Seamer wrote.
"Over the years and certainly during my time at Supercars, we have been keen to encourage more comments and opinion from teams and drivers, and to increase driver engagement with our media partners and fans.
"But as in all sports, there is a line that must not be crossed, where malicious and unfounded accusations made against specific teams, drivers or stewards go beyond robust competition, and start to bring the category and sport into disrepute.
"The recent comments likening Scott McLaughlin to Lance Armstrong and similar offensive commentary err into the realm of bringing the sport into disrepute.
"The comments are a clear allegation of cheating, and implicate Scott and his team, as well as Supercars and [the Confederation of Australian Motorsport's] stewards."
Supercars is also in the process of reiterating its social media policy to teams and drivers.
The email was sent after McLaughlin and his team - DJR Team Penske - met with Seamer to discuss the abuse, which has taken its toll on the 2019 champion.
Pye, Jamie Whincup and Dave Reynolds are among the drivers who have publicly criticised McLaughlin, after he was allowed to keep his "tainted" Bathurst title.
After McLaughlin secured the 2019 drivers championship crown earlier this month, he labelled the past few weeks as a "tough month", before calling his rivals "toxic". That led Kiwi motorsport legend Greg Murphy to suggest McLaughlin should consider quitting Supercars.
McLaughlin has also received some support, with drivers Cam Waters and James Courtney leaping to his defence.
Waters told AAP other drivers were just jealous of his success, while Courtney believed McLaughlin should do his talking on the track.
The final race of the Supercars season takes place in Newcastle on Sunday.
