Following offers of work, a number of Filipinos have traveled there on tourist visas but later found themselves in fake or forced marriages with Japanese citizens, Manila's foreign department said in a statement.
The department recorded six human trafficking cases involving Filipinos who sought work in Japan last year, spokesman Charles Jose told AFP.
Two were sexually exploited and four were made to work against their will, he added.
"Be mindful not to interact with those who promise employment in Japan but end up... inducing a person to engage in fake or forced marriages with Japanese nationals for the purpose of exploitation," the department said in an advisory.
"Foreign tourists are not allowed to work in Japan. Working while having a tourist visa is considered an immigration violation and a criminal offence, and may lead to incarceration and deportation," it added.
About 10 million Filipinos, or a tenth of the population, work abroad to escape widespread poverty and scant job opportunities at home, official estimates show.
A quarter of the population live on $1.30 a day or less.
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