It is said that those who acquire tattoos in youthful haste, or while under the influence, regret them in later life.

But proud or repentant about their body art, more than 100 employees at the Osaka city government may have to have their tattoos removed or search for another job following the local mayor's crackdown on tattoos.

Toru Hashimoto, a 42-year-old lawyer who became mayor of Osaka late last year, ordered a survey of tattoo ownership among more than 30,000 employees after complaints that a welfare officer had intimidated children by showing off his inkwork.

Tattoos, especially large, intricate motifs of mythical beasts and shogun-era courtesans, are traditionally associated in Japan with yakuza gang membership.

These days, however, the modest designs occasionally visible on the arms, necks and legs of young Japanese people are more fashion statement than evidence of antisocial tendencies.

Even so, swimming pools and public baths ban tattoos in principle, or at least request that they be covered up; and many major employers, including Japan's two biggest airlines, ban staff from having any kind of tattoo.

The Osaka survey asked employees to voluntarily report any tattoos on their arms, legs, heads or any other part of the body that is visible to members of the public while they are on official duty. They were also asked to provide details about concealed tattoos, and how long they had had them.

The poll found that 98 workers were tattooed on visible parts of their body, 12 on concealed areas, and another 16 on both, according to the Asahi Shimbun newspaper.

The government is now considering whether to ask the employees, most of whom work in waste disposal and public transport, to have their tattoos erased, or even to find another job.

Hashimoto, a rightwing populist who is thought to harbour ambitions for high national office, relishes confrontations with the city's public servants.

Earlier this year, he introduced regulations forcing teachers to sing the national anthem at school ceremonies.

He appears to be intolerant of workers who choose to embellish their bodies with works of art, however small or innocuous. Some of the tattoos revealed in the survey were hardly vicious: sea turtles, moons and dolphins, according to the Asahi.

"Some workplaces may tolerate tattoos, but that shouldn't be the case for public servants," Hashimoto said when the results of the survey were released on Wednesday. "If they insist on having tattoos, they had better leave the city office and go and work in the private sector."

Not all of Osaka's public servants are happy with Hashimoto's tattoo policy. About 800 teachers and other school workers refused to respond to his survey, saying it infringed on their right to privacy. A local lawyers' group had asked the city to cancel the investigation, calling it a violation of human rights.

Hashimoto's crusade may have been influenced in part by his upbringing: during his mayoral campaign, weekly tabloids claimed that his deceased father and uncle were both gangsters, although it is not known whether they had tattoos.

Ambitious politicians in Japan can rest assured that body art need not be an obstacle to high office. Matajiro Koizumi, the grandfather of the former prime minister, Junichiro Koizumi, served as posts and telecommunications minister despite sporting a large tattoo of a red dragon on his back.