Stadler has come under fire for how he has handled the fallout from parent company Volkswagen's diesel emissions scandal. Munich prosecutors have been investigating Audi on suspicion of fraud and criminal advertising in the United States, where the Volkswagen scandal broke in September 2015.
Stadler only got a five-year contract extension last month because of an agreement among supervisory board members that he would not serve out his full term, two sources close to the company's supervisory board have told Reuters.
An Audi spokesman said: "We deny plans to get rid of Stadler," adding that he declined to comment on the content of the dossier. Volkswagen is looking at rehiring the chief executive of General Motors' Opel, possibly to lead Audi, a source familiar with the matter told Reuters this month, following his resignation from Opel.
Bild am Sonntag also quoted Oliver Blume, the head of Porsche, Volkswagen's sportscar division, as saying he had no interest in replacing Stadler. "I have a dream job and am very happy at Porsche. Nothing else comes into question for me." (Reporting by Georgina Prodhan; Editing by Nick Zieminski)