A disgraced self-help guru who ran a secret cult, where women were branded with his initials and ordered to have sex with him, has been sentenced to 120 years in prison.

Keith Raniere founded a "personal and professional development" company called NXIVM (pronounced nex-ee-um) in 1998 in Albany, upstate New York.

But during his trial, prosecutors said NXIVM was in fact a cover for a sex cult that manipulated and brainwashed dozens of victims, putting some on starvation diets.

Victims told of how they had to hand over embarrassing photographs and documents that were kept as collateral to keep them quiet about what was going on.

His control was apparently so absolute that one woman testified about how she was confined to a single room for two years after she said she was attracted to someone else.Advertisement

NXIVM charged thousands of dollars for invitation-only self improvement courses at its New York headquarters, along with branches in Mexico and Canada.

Members included millionaires and Hollywood actresses willing to endure humiliation and pledge obedience to the defendant as part of his teachings.

Rainere, 60, was convicted last year of crimes including racketeering, smuggling, sex trafficking, extortion and obstruction of justice.

He remained unrepentant, saying: "I do believe I am innocent of the charges... It is true I am not remorseful of the crimes I do not believe I committed at all."

US District Judge Nicholas Garaufis called him "ruthless and unyielding" in offences that were "particularly egregious" because he targeted young girls and young women.

He handed down the sentence in federal court in Brooklyn after a lengthy hearing that included victims' statements.

Prosecutors claim Raniere led a criminal enterprise, inducing shame and guilt to influence and control co-conspirators who helped recruit and groom sexual partners for him.

During his sentencing, Raniere was heavily criticised by former followers, including India Oxenberg, the daughter of Dynasty actress Catherine Oxenberg.

India Oxenberg called him an "entitled little princess" and a "sexual predator" and lamented she "may have to spend the rest of my life with Keith Raniere's initials seared into me".

Prosecutors had sought life in prison for him while defence lawyers said he should face 15 years behind bars.