Yokohama's website said Sunday they would indefinitely bar one of their supporters from their matches for committing an unspecified "act of provocation" against an unnamed Kawasaki Frontale player in the home match the previous night.

Yokohama won the match 2-0.

The male supporter was seen on television and later on social media as he waved a banana in a section behind Yokohama's net in the 42nd minute as Kawasaki striker Renato moved in front of him.

When asked if the supporter, identified only as a man in his late teens, was taunting the 26-year-old Renato, Yokohama president Akira Kaetsu told Japanese media on Saturday: "From an objective point of view, it is highly possible."

"There is unlimited suspicion," he said about the possibility of banana-waving being construed as racial discrimination.

The man told Yokohama officials he had committed an "act of provocation" which was however "in no way aimed at anyone in particular", according to press reports.

It was the second incident of rare racial abuse in Japanese football this year but it remains to be seen whether the J-League will punish Yokohama.

In March, Urawa Reds were ordered by the league's authority to play behind closed doors after fans unfurled a "Japanese Only" banner at a home match.