A growing number of piracy websites are taking advantage of the global popularity of Japanese manga to illegally sell foreign-language versions.

The Authorized Books of Japan, or ABJ, says a survey conducted in February found 1,207 sites were offering pirated titles. The ABJ also says 913, or more than 70 percent of these sites were in English, Vietnamese and other foreign languages.

The ABJ notes that the use of Japanese piracy sites plunged significantly after publishers and organizations took steps to tackle the problem. But it adds that foreign-language versions of such sites have been expanding in recent years, mainly targeting people in Southeast Asian countries.

The organization estimates that these foreign-language sites have at least five times the traffic of the Japanese ones. It says the losses from copyright infringement are probably much higher as well.

Multiple illegal apps guiding users to overseas piracy sites are available on official app stores.

Major Japanese publisher Kadokawa said that in February last year it confirmed at least five apps linked to illegitimate foreign-language sites on app stores operated by Google and Apple. These apps were removed after the publisher took legal action.

A Japanese industry group, the Content Overseas Distribution Association, or CODA, says it is difficult to identify overseas piracy sites through official app stores, as display methods vary across countries and regions.

CODA is calling for measures to address the issue. It says the publishers of legitimate foreign-language versions are seeking consultations about the losses they have suffered.