TOKYO (Reuters) -Takeshi Niinami, one of Japan's best-known business leaders who is the subject of a police investigation into his purchases of supplements, said on Wednesday that he believed that the products were legal.

He resigned this week from his roles as CEO and chairman at drinks group Suntory Holdings following the police investigation.

"I didn't breach the law and I am innocent," he told a briefing for the influential Keizai Doyukai business lobby which he chairs.

Japanese media have reported that police in Fukuoka prefecture are investigating whether supplements containing THC, the psychoactive component of cannabis, had been sent to Niinami's home.

Reuters was not able to reach Fukuoka police officials for comment.