A Korean immigrant housekeeper has accused her former employers — a Korean Buddhist monk and his family — of keeping her as a prisoner in their homes in Queens for 12 years and forcing her to work as their “slave” under threat of death, according to a lawsuit filed in federal court in Manhattan.

The housekeeper, Oak-Jin Oh, 60, has alleged that the family forced her to work long hours without pay, deprived her of medical care when she was sick and “usually” refused to give her a bedroom or a bed to sleep in.

Though the family allowed her outside their homes from time to time — she was permitted to go to the grocery store to buy food for the family’s meals — they used threats to dissuade her from reporting her situation to the authorities, the lawsuit alleges.

“She was threatened with reputational harm, physical harm and death,” the lawsuit says.

The suit, filed last week, names the family patriarch, Soo Bok Choi, a Buddhist monk, as a defendant, as well as two of Mr. Choi’s brothers, his son and daughter, a niece and the personal representative of the estate of his mother, who died in 2009.