A pair of bears picked the wrong person to mess with Thursday in Japan when they approached a 50-year-old karate practitioner only to be kicked away, police and media said.

Masato Fukuda was lightly injured in his encounter with the bears on Thursday morning in Nayoro city, on the northern island of Hokkaido, police told AFP.

The man was visiting from Japan's central Aichi region to see a waterfall in Nayoro's mountainous area when he chanced upon the two brown bears poking their faces out of bushes, the Mainichi newspaper reported.

One of them came towards him -- but unfortunately for the animal, Fukuda was experienced in the martial art of karate, according to media reports.

"I thought I should make my move or else I will be killed," he told a local broadcaster.

Fukuda kicked it in the face -- twice -- and in the process twisted his leg, but his attack swiftly scared away the hapless duo, reports said.

Both animals looked to be about 1.5 metres (five feet) tall, according to media.

Brown bears can weigh half a tonne (1,100 pounds) and outrun a human.