TOKYO — In between chanting fans at Japan's Tokyo Dome baseball stadium race an army of women in fluorescent uniforms carrying unwieldy backpacks with attached spray guns.

These are the "uriko" — beer vendors who are as unique to Japanese baseball as the cheering sections that beat drums and blow horns to rally their teams.

Made up almost exclusively of young women in miniskirts or shorts, the tradition might appear outdated to some, like the cheerleaders who somersault onto the field between innings.

Japan has had its own low-key #MeToo movement, and women in recent years have challenged everything from high heels at work to traditions requiring they serve tea to colleagues.

But the uriko remains a firm favourite with fans of Japan's most popular sport, which attracts a diverse crowd of men and women, as well as many families.

Ms Honoka Hagiwara, who carries a keg weighing up to 15kg on her back for upwards of three hours at a time, said she was attracted by the job's "glamorous" image.

"I've been doing it for just over a year now and I've got much more used to it," the 22-year-old told AFP.

She concedes it was "physically very tough" at first, but now enjoys the highly competitive job, with over 100 rivals working any given game.

At Tokyo Dome, home to Japan's most popular baseball team, the Yomiuri Giants, vendors sell an average of about 20,000 glasses of beer at a night game.