US prosecutors have dismissed charges against two New York prison guards who admitted to falsifying records on the night the US financier Jeffrey Epstein took his own life in his cell in 2019.

The decision came a day after Epstein's long-time associate British socialite Ghislaine Maxwell was found guilty of recruiting young girls to be sexually abused by him.

Federal prosecutors signed a "nolle prosequi" to drop charges against former guards Tova Noel and Michael Thomas after the two completed community service work as part of an earlier legal agreement.

The New York prison warders had been indicted in November 2019, three months after Epstein's death in his cell in August as he was awaiting trial for sex crimes.

They were accused of not having made their rounds on the night of 9 to 10 August 2019, and of having remained in their office, browsing the internet.

The two guards admitted to forging documents to make it appear that they had made their rounds that night.

Epstein, a multimillionaire financier and member of the US and international jet set, was found dead at dawn on 10 August.

The autopsy concluded suicide, although his sudden death in custody fuelled widespread controversy and conspiracy theories.

Then-US attorney general William Barr denounced "serious" lapses in the allegedly secure prison where Epstein had been held since his arrest in July 2019 and prosecuted for sex crimes, in particular against young girls.

Ghislaine Maxwell faces a decade in prison for trafficking young girls

On Wednesday, Epstein's companion and accomplice Maxwell was found guilty by a Manhattan federal court of a series of crimes, including trafficking in young girls between 1994 and 2004 for the benefit of Epstein.

Maxwell, 60, faces decades in prison, although a sentencing date has not yet been set.

Her brother Kevin Maxwell told ABC News that he was convinced of his sister's innocence and that her appeal would prove successful, even though he believed Epstein was guilty of the crimes he was charged with.

"The reality is that there are myriad jury cases, miscarriages of justice involving juries, where the verdicts have been overturned on appeal. This will just be yet another one," Mr Maxwell said.