TOKYO -- Japanese drug enforcement officials say they fear Japan has been targeted by South American cocaine syndicates that view this nation's wealthy consumers as a potentially lucrative new market.

Unlike many Western countries, Japan has largely been spared the drug plague. Health officials reported only 12 heroin addicts last year and a sprinkling of regular marijuana smokers. Only stimulants -- pep pills -- constitute a major drug abuse problem, according to police and health officials. But recently cocaine has begun to show up here, smuggled to Japan from Colombia, Bolivia and Brazil. In the last five months alone, police have seized more cocaine than in all the years since the end of World War II combined.

The confiscated amounts still are tiny -- about half a pound in 1988, 30 pounds last year and about 155 pounds so far this year -- but the trend is causing alarm among drug enforcement officials here.

"We are very much worried about it," said Kenya Takizawa, the Stanford Business School-educated deputy director of the National Police Agency's drug enforcement division. "The amount is not very much for America, but it is phenomenal for Japan."

Takizawa and others say they believe Colombia's Medellin cartel and other South American cocaine groups are "testing the market" in Japan. They are doing so, Takizawa said, because the U.S. cocaine market is saturated and because beefed-up drug enforcement efforts in the United States and Europe have made it more difficult to peddle illegal drugs there.

In addition, prices charged for drugs in Japan, like those for nearly everything else, are much higher than elsewhere in the world, bringing greater profits for drug dealers. According to Stanley Furce, the Drug Enforcement Agency attache at the U.S. Embassy here, cocaine goes for about $18,000 to $20,000 a kilogram (about 2.2 pounds) in the United States and for about three times that amount in Japan.

Despite the higher prices, demand for cocaine among Japanese appears to be growing, spurred in part by increases in wealth and leisure time here.

Takizawa said a boom in overseas travel by Japanese has been an important factor in exposing people to cocaine. About 10 million Japanese have gone abroad each year, and some come back "with a little bit of the drug culture," he said.

"Most young people try it overseas and never intend to use it in Japan. But some, maybe, are using it on the soil," he added.

Concerned about the potential drug threat, the government two years ago agreed to set up its first drug information clearing house. The Drug Abuse Prevention Center is still the only one of its kind in Japan, compared to about 1,400 similar centers in the United States, according to Shunzo Abe, an official with the center.

The center, which is supported by the Health Ministry and the National Police Agency, recently published two comic book-style explanations of the perils of drug use and has provided pamplets and other literature to schools.

Health officials and police say they believe the drug problem is unlikely to become as severe here as in the United States. Japan's laws are considered much tougher, with mandatory, often long prison terms, no plea-bargaining and rehabilitation through cold-turkey withdrawal from drug use in jail cells.

"Here even the simple user will go to jail," said Kazuko Kimura, deputy director of the Health Ministry's narcotics bureau. "We think that is a strong deterrent." In contrast to the United States, Japan has no low-income underclass to provide a core population of drug abusers and addicts.

In addition, social acceptance of even casual drug use remains very low, although urban youths apparently are experimenting with marijuana in increasing numbers, according to news reports here. "I think Japanese draw a clear line between legal and illegal activities," said Takizawa.

Thus, Japanese men, who often drink to excess as part of Japan's after-hours work culture, are rarely criticized for it, and such drinking may even be received with gentle humor. But when a 28-year-old television writer was arrested for possession of marijuana recently, newspapers reported that he had "disgraced" his TV show by his acts.

Japan has had drug problems in the past. The stimulant methamphetamine was a major problem after World War II, when wartime stockpiles made their way onto the black market. The drug is said to have been stockpiled during the war to motivate kamikaze pilots and overworked factory employees. Tougher laws after the war got the problem under control, Takizawa said.

In the early 1960s, a surge occurred in use of heroin, smuggled in from Southeast Asia. But after a police crackdown, heroin has mostly disappeared from Japan. Stimulants resurfaced in the 1970s, and police and health officials have long tried without much success to wipe them out. About 17,000 people were arrested last year for using, possessing or selling methamphetamines, according to police statistics.

Furce and others cited the rise in use of stimulants as an indication that Japan could also face severe problems with cocaine, a stimulant.

"Japan, too, needs to take active steps to cooperate in the war against drugs," the Asahi Shimbun newspaper warned in a recent editorial. "No longer is it someone else's problem."