The National Police Agency claimed Thursday that 83 women were trafficked into Japan and forced to work in the sex industry in 2003, up 28 from the previous year.
By nationality, the largest number came from Colombia, at 43, followed by Thailand, with 21 and Taiwan, at 12.
A U.S. report on human trafficking has labeled Japan as the worst industrialized country in terms of measures aimed at preventing the trafficking of women.
Human rights groups and researchers estimate that thousands of women -- mostly from poor Asian countries -- are trafficked into Japan every year and forced to work in the sex industry.
An NPA official said the agency's figure only reflects the number of cases reported by prefectural police last year. He did not comment on the larger picture of human trafficking in Japan.
Police dealt with 20 cases of human trafficking across Japan in 2003, up four from the previous year. It arrested or sent to prosecutors cases on 41 suspects, up 13.
The numbers of female victims, suspects and cases were all the second-highest figures on record after 2000, when the NPA began compiling data.
In one case, police in Tokyo and 17 other prefectures, in cooperation with immigration authorities, raided 24 strip clubs across the country in February 2003, arresting 15 people and taking 68 foreign women into custody.
One woman came to Japan after being told she could find work at a confectionery factory. But her broker told her she had to cover traveling and other costs worth 5 million yen and she was forced to work at a strip club and as a prostitute, police said.