Mariah Carey's sister is suing their mother for alleged sexual abuse.

Alison Carey, 57, has accused her mother Patricia of forcing her to perform sex acts on strangers at the age of 10 and she has now filed a lawsuit at the State of New York Supreme Court.

The Sun newspaper's Bizarre column revealed that the lawsuit states: "Defendant, who is Plaintiff's mother, allowed and encouraged other male persons whose identities are at present unknown to engage in sexual acts as defined in New York Penal Law, specifically 130.52 (forcible touching), and 130.65 (sexual assault in the first degree), while Plaintiff was approximately 10 years of age.

Alison Carey has made shocking allegations about her childhood. Photo / Supplied
Alison Carey has made shocking allegations about her childhood. Photo / Supplied