An Afghan man on trial over illegal entry into Japan has sued the government, seeking nullification of its decision not to recognize him as a refugee and cancellation of his detention.

Abdul Aziz, 30, filed the lawsuit on Monday with the Hiroshima District Court after applying for immigration authorities to release him from custody following a court ruling that he should be granted refugee status.

"The decision not to approve refugee status is illegal as it is apparent that he (Aziz) applied as a refugee coming from the Hazara minority ethnic group and fears being religiously and politically persecuted," papers filed with the court said.

Aziz entered Japan via Fukuoka airport on a fake passport in June 2001 and worked as a secondhand car-parts dealer around Yamaguchi Prefecture before he was arrested on suspicion of illegal entry, according to the suit.

He was indicted in March but last month the Hiroshima District Court decided not to punish him, despite finding him guilty, saying, "He should be approved as a refugee, as he belongs to the Hazara ethnic group and is likely to face threats in Afghanistan due to his ethnicity." Prosecutors have appealed that ruling.

He applied for refugee status in November, but his application was rejected by immigration authorities who said he could not provide proof that he would face threats in Afghanistan, according to the suit.