A Japanese support group has called on the government to take measures to prevent grown-up children of Filipino women and Japanese men from getting into trouble when they come to Japan in search of their Japanese parent.

The number of such cases is rising as women who were in Japan on entertainer visas gave birth in the early 2000s and their children have come of age.

The number of Filipino women who were in Japan as singers, dancers or other entertainers peaked at over 80,000 in 2004.

Their number declined after the Japanese government tightened the issue of entertainment visas.

An increasing number of grown children are seeking to come to Japan to obtain Japanese citizenship or find their biological father.

The Solidarity Network with Migrants Japan says some of them have found themselves in unreasonable debt or have been forced to do work they did not sign up for.

On Friday, the group submitted a request to Japan's Foreign Ministry and the Justice Ministry to cooperate with the Philippine government so that the adult children can take a training program to learn about Japanese law and living in the country before they arrive.

Ito Rieko, who submitted the request, said she wants the government to take steps to protect the offspring of Japanese fathers as Japanese nationals.