As Japan braces for a fresh influx of foreign workers from the new visa system starting next month, small and midsize firms fear the system will end up helping only major firms in large cities, since those who qualify for the two new "specified skills" visas will be free to switch companies in the same sector.

Although the immigration law was revised to cope with the nation's severe labor shortage, small companies feel they will continue to struggle to secure competent workers because they have to compete with big-name companies offering higher pay.

Foreign trainees who meet certain criteria also will be able to switch to one of the new visas without extra testing, so companies are additionally concerned they might suddenly decide to go and work for a bigger company.