FOUR major Japanese Internet service providers (ISPs) have decided to stop providing fee-based services that allow customers to access websites featuring photographs of very young Japanese girls dressed in swimsuits and adopting sexually provocative poses.

Initially, the ISPs were reluctant to halt their services, insisting the photographs did not constitute child pornography under current laws.

However, under mounting criticism that they were commercialising the sexualisation of children, one pulled its service on Monday, with two others following suit on Tuesday. The last one has said it intends to withdraw its service in the near future.

Experts have long lamented Japan's tardy approach in dealing with child pornography, with some saying photographs similar to those on the websites are considered illegal in some countries.

The firms that have decided to end the controversial services are @nifty, OCN, Biglobe and So-net, which are managed by subsidiaries of Fujitsu Ltd, NTT Communications, NEC Corp and Sony Corp respectively.

The photos are carried in special membership sections (or "corners") bearing names such as imoto (younger sister) and sho-chugakusei gentei (primary and middleschool students only).

For about 3,000 yen (S$41) a month, users can access many different photographs taken by production companies. To attract potential customers, non-members can view a few photos of each girl for free.

Although the girls are not naked, their scanty clothing - often bikinis - and the poses they adopt are clearly sexual in nature.

In one photo, a girl who is introduced as being 10 years old is shown on a bed changing into a bikini, while in another, a supposed seven-year-old jumps over a vaulting horse wearing school swimwear.

The ISPs first introduced these portal services in 2003.

The specific wording of Japan's Child Prostitution Law and the law banning the public display of pornographic images of children are thought to lie behind the current problem.

These laws define child pornography as "the stimulation of sexual desire via the depiction of a naked or partially-clothed child".

A member of the Japan Committee for the United Nations Children's Fund (Unicef), which wants child-pornography regulations tightened, said: "Under this definition, the images in question featuring children in swimsuits are not considered illegal."

After the Metropolitan Police Department arrested three men last October over the production of DVDs featuring a girl in a bikini, the threesome were found guilty under Japan's Child Welfare Law instead.

Such DVDs have been attracting the attention of the Unicef committee since 2000 - and their content has become increasingly risque.

"Judging from the girls' clothing and unnatural poses, it's clear these services are targeting paedophiles. These photos could affect the girls' future employment and marriage prospects," a committee member said.

"It's unbelievable that supposedly socially-responsible major ISPs offer such services."