A German senior executive of the Japanese arm of Volkswagen AG was arrested Wednesday for the alleged use of a stimulant drug, police said.

Thomas Siebert, 53, is suspected of using the drug in Tokyo or vicinities early this month. The senior corporate executive officer of Volkswagen Group Japan admitted to using cocaine but denied the use of any other illegal drugs, the police said.

The police searched Siebert's home in Tokyo's Minato Ward early this month based on information presented by Kawasaki Overseas Mail Sub-Branch in Kanagawa Prefecture, southwest of Tokyo, Yokohama Customs said.

The German national tested positive following a urine test, the police said, adding they are investigating how he obtained the drug.

According to Volkswagen Group Japan, Siebert assumed his post in 2010 and worked mainly at its Tokyo office.

"It is extremely regrettable and we deeply apologize," the company said in a statement, adding it will fully cooperate in the investigation.