A Chinese man facing deportation on Wednesday lodged a protest with a Kyushu bar association over his 18-month detention.
Ma Haoping, 48, entered Japan in the late 1990s claiming to be related to a Japanese left behind in China in the chaos at the end of World War II.
He is appealing a deportation order along with six other Chinese who came to Japan claiming to be blood relatives of 63-year-old Tsuruji Inoue of Kumamoto Prefecture.
Inoue resettled in Japan in 1983.
In the protest, he claimed his detention since December 2001 at an immigration facility in Omura, Nagasaki Prefecture, is a grave violation of his human rights.
Ma is the only one among the seven not allowed temporary release. In November 2001, Japanese authorities found out that the seven entered Japan using the false kinship claim.
Two women in the group claimed to be Inoue's daughters, but they turned out to be his stepdaughters -- children born to Inoue's Chinese wife and her former husband. Ma is married to one of the women.
The seven asked the Fukuoka District Court to overturn the deportation order against them, but it refused. They are now appealing the court's decision.
A lawyer for Ma told reporters that his health is worsening as a result of being separated from his family, and said further detention would be inhumane.