A former school headteacher, who reportedly paid for sex with 12,000 women in the Philippines, has been convicted in Japan for taking photos of naked Filipino girls.

The Yokohama District Court sentenced Yuhei Takashima, 65, to two years in prison with the term suspended for four years, a spokesman told AFP.

Takashima, who reportedly had sex with girls as young as 14, escaped prison with a promise not to offend again.

Quoting the verdict, Japan's Jiji Press said the girls pictured were "aged between 12 and 14" and were photographed at a hotel in the Philippines about two years ago.

According to local media, Takashima had meticulously catalogued nearly 150,000 photographs of his sexual encounters over a 27-year period in around 400 separate albums.

Takashima was quoted as having said in court that he "has a habit of collecting things" and wanted "to keep the memories".

The former middle-school principal started paying for sex when he was dispatched to a Japanese school in Manila in 1988.

He later went on three sex tours a year to the country, making a total of 65 visits.

During that time, he had sex with more than 12,000 women, with Nippon TV saying they were aged between 14 and 70.

Presiding judge Naoko Omori called Takashima's action "despicable and vicious," saying he "took advantage of the economic plight of young girls" in the Philippines, according to Jiji.

"Either in Japan or in the Philippines, children should be protected. He should have known that as a teacher," she said.

Takashima should be condemned for "repeating indecent acts habitually to fulfil his sexual desire" but he "pledged he will never do it again," she said, according to public broadcaster NHK.

Prosecutors had reportedly sought a two year prison term.

In Japan, possession of sexual images or videos of people under 18 can result in jail time after the government overhauled laws that had only banned the production and distribution of child pornography.

The changes came into effect this summer, but it does not include drawings or digitally-created imagery.

Anyone who "possesses child pornography for the purpose of satisfying his/her sexual interest" faces imprisonment of up to one year or a fine of up to one million yen ($8,300), according to the justice ministry.