According to Reuters, the case has highlighted a growing crackdown on foreigners living in Japan without visas and prompted demands for her release.
The agency quoted Obueza’s lawyer as saying she was detained two weeks ago after authorities turned down an appeal against her asylum rejection.
Obueza, 48, campaigns for asylum seekers and the 4,700 people on “provisional release” from immigration detention – a status that lets foreigners out from detention but bars them from working and travelling freely.
Her arrest is part of a wider campaign by the justice ministry, which in September 2015 said it would take steps to reduce the 60,000 foreigners living in Japan without visas.
People on provisional release, many of whom have lived in Japan for decades, have been among those targeted, according to Reuters.
“Elizabeth was targeted and detained for being an activist,” said immigration lawyer Shoichi Ibusuki. “I want her released immediately.”
The crackdown on people like Obueza comes even as people on provisional release, despite being legally unable to work, power Japan’s construction and manufacturing sectors as companies scramble to find workers in the worst labour shortage in decades.
“Elizabeth is held in solitary because she’s an activist and immigration officials don’t want her causing trouble,” said Mitsuru Miyasako, head of the provisional release association in Japan, a group representing refugees and immigrants.
“Locking someone up alone in a tiny room is to ruin them psychologically.”
Isolation has not stopped Obueza from fighting for detainees’ rights.
“When I go outside my room, I go around the windows and talk to the others,” Obueza said. “I advise them what to do.”