The leader of gender equality group Time's Up has resigned due to her alleged efforts to discredit a woman who accused New York Governor Andrew Cuomo of sexual harassment.

A report released last week alleged lawyer Roberta Kaplan reviewed a draft letter questioning the complainant's character.

The same report found that Mr Cuomo sexually harassed 11 women.

Mr Cuomo, 63, denies any wrongdoing and has so far resisted calls to resign.

The report by Attorney General Letitia James's office found that Mr Cuomo's alleged behaviour against women had violated state and federal law.

The investigation took months and involved interviews with almost 200 people, including staff members making complaints against him.

Time's Up was founded during the #MeToo movement by Hollywood women to fight sexual harassment.

Ms Kaplan's resignation as chair of the group's board of directors "is the right and appropriate thing to do", it said in a statement.

Last week's report found that Ms Kaplan had reviewed a draft of an unpublished op-ed letter that was aimed at attacking the character of Lindsey Boylan, a former aide to Mr Cuomo who was the first to publicly accuse him of sexual harassment.

"Unfortunately, recent events have made it clear that even our apparent allies in the fight to advance women can turn out to be abusers," Ms Kaplan wrote in a letter submitting her resignation from the group, according to the New York Times.

"We have felt the raw, personal and profound pain of that betrayal."

Her resignation came after past supporters of Time's Up penned an open letter on Monday calling for an investigation, stating that the group's leaders "align themselves with abusers at the expense of survivors".

Mr Cuomo has so far resisted calls to resign, including one from President Joe Biden, but may soon face impeachment by state lawmakers.

He denied specific allegations to investigators and said in a statement last week that he had "never touched anyone inappropriately or made inappropriate sexual advances".

On Sunday his top aide, Melissa DeRosa, announced her resignation.

An executive assistant to Mr Cuomo has waived her right to anonymity and called for accountability over his alleged sexual harassment.

"What he did to me was a crime," Brittany Commisso, 32, said about alleged instances of groping while she worked under the governor.