Japan is considering detaining some asylum seekers once their visas expire in an attempt to curb what it calls abuse of its refugee system, drawing criticism from lawyers who say such measures risk causing humanitarian harm.

Exchange students and foreign trainees who apply for asylum may be held in immigration detention centers once their visas expire, Yasuhiro Hishida, a justice ministry official overseeing asylum recognition, said Friday.

Currently, people with valid visas who apply for asylum receive six-month, renewable permits that allow them to stay and work in Japan while their applications are reviewed.