Nearly 5 percent of Japanese adults are addicted to gambling, a rate up to five times greater than most other nations, according to a study released to local media on Wednesday.

The study also showed rising adult addiction to the Internet and alcohol in a society long known for its tolerance of boozing and a love of technology.

"If something new becomes available, addiction will only rise," SusumuHiguchi, Japan's leading expert on addiction, who headed the study, told local journalists, Japanese newspaper Asahi Shimbun reported.

The survey, conducted last year and sponsored by Japan's health ministry, came as the Japanese government considers controversial plans to legalize casino gambling in certain special zones, with some saying it would boost the number of foreign tourists.

A lack of public awareness of the perils of gambling addiction - despite a robust gaming industry - separates Japan from other industrialized nations that are relatively more willing to talk openly about the problem, saida campaigner.

Researchers estimate that roughly 5.36 million people in Japan - 4.8 percent of the adult population - are likely pathological gamblers who cannot resist the impulse to bet, Yomiuri Shimbun reported.

The study said 8.7 percent of men and 1.8 percent of women fit the internationally accepted definition of addicts, according to Mainichi Shim-bun.

The wide availability of pachinko parlors - loud, colorful salons that offer rows of pinball-like games - and other gambling establishments is believed to be contributing to the problem.

The ratio of compulsive gamblers in most nations "stands more or less around 1 percent of the adult population. So Japan's ratio is high," a member of the study group told reporters.

Gambling is everywhere in Japan, with pachinko halls dotted around train stations and along major roads, attracting many middle-aged men, as well as women and young people.

Betting on racing - horses, bicycles, motorbikes and speedboats - is also common, with horse racing featuring on weekend television.

"There is an absolute lack of preventive education for addiction," said Noriko Tanaka, head of an activist group called Society Concerned About the Gambling Addiction.

Japan has allocated insufficient social resources to publicly discuss the problem, while more open efforts are made in this regard in the United States and Europe, she said.

Open discussion of the gambling addiction is rare, as Japanese people generally shy away from disclosing what can be regarded as family dishonor, Tanaka said.

"We are not calling for a ban on gambling, and we recognize it has its own economic merits," she said. "But we must also discuss the negative economic and social impacts."

The study questioned 7,000 Japanese adults nationwide, of whom 4,153 gave valid answers.

Around 4.21 million adults are believed to show signs of Internet addiction, the study found, a rate that had risen 50 percent in five years.

Researchers blamed the spread of smartphones and the increasing quality of digital content for the rising number of Internet addicts, who often prefer their electronic devices over other essential activities such as sleeping, according to a Nikkei newspaper report.

More than a million people were believed to be addicted to alcohol, compared with an estimated 830,000 a decade ago, the newspaper reported.