Time’s Up leader Roberta Kaplan has resigned over fallout from her work advising New York governor Andrew Cuomo’s administration when the first allegations of sexual harassment were made against him last year.

Ms Kaplan cited her work counselling the administration last winter and her more recent legal work representing Melissa DeRosa, a top aide to Mr Cuomo who resigned on Sunday, nearly a week after a report by the state attorney general concluded that the governor had sexually harassed 11 women.

Time’s Up tweeted on Monday that Ms Kaplan had stepped down from the board, saying: “We and she agree that is the right and appropriate thing to do.”

According to The New York Times, Ms Kaplan wrote in her resignation letter: “I therefore have reluctantly come to the conclusion that an active law practice is no longer compatible with serving on the board at Time’s Up at this time and I hereby resign.”

Ms Kaplan was the chair of the board of directors of Time’s Up and co-founder of the Time’s Up Legal Defence Fund, which aids women who have experienced sexual harassment and discrimination in the workplace.

The Time’s Up organisation wrote in a statement that its staff have worked in “those very institutions” it is trying to hold accountable.

“We have never felt co-opted by that experience, only informed by it to try new strategies,” reads the statement.

“And we are proud of that work and the change we have achieved. Yet, we recognise that this work has sometimes resulted in a lack of trust from the broader survivor community we serve and to which we also belong.”

The group is facing pressure from survivors and victims who sent an open letter on Monday demanding an independent, third-party investigation.

It also pushed for Time’s Up to cease “all partnerships” with and return any donations from individuals and corporations with active sexual assault or harassment allegations.

“There is a consistent pattern of behaviour where the decision-makers at Time’s Up continue to align themselves with abusers at the expense of survivors,” the letter reads.

“Time’s Up should be ashamed.”

Meanwhile, the Human Rights Campaign (HRC) said it is launching an internal investigation over the advocacy organisation’s leader Alphonso David’s inclusion in the attorney general’s report.

It said: “Over the past several days, HRC’s employees, supporters, board members and partners have raised questions about the appropriateness of Alphonso David’s actions and whether they align with HRC’s decades’ long mission of fighting for equality and justice for all.”

Both Ms Kaplan and Mr David, a former legal counsel for the governor, were consulted by the Cuomo administration when he was first accused of harassment by a former economic development adviser, Lindsey Boylan.

At the time, Ms Boylan was alone in accusing Mr Cuomo of misconduct and the governor and his administration had drafted a letter attacking her credibility and motives, with the intent of circulating it publicly.

Ms Kaplan and Mr David both agreed to review the letter.

A report by New York’s attorney general, released last week, said Ms Kaplan told the administration that with some adjustments, it would be fine to send out.

Mr David declined to sign the letter, but agreed to contact other people to see if they would.

Other advisers, though, said that it was a bad idea and the letter was never widely disseminated.

Ms Kaplan and Tina Tchen founded the Time’s Up Legal Defence Fund in 2018 to provide legal defence for sexual violence victims.

She successfully represented marriage equality pioneer Edith Windsor before the US Supreme Court in 2013, winning the case that struck down laws against same-sex marriage across the United States.

She later published a book about the case titled Then Comes Marriage.

Ms Kaplan also represents writer E Jean Carroll, who filed a defamation lawsuit against Donald Trump in 2019 related to her claim that the former president raped her in a department store dressing room in the 1990s.

Ms Kaplan is an adjunct professor at Columbia University Law School and was a partner at Paul, Weiss, Rifkind, Wharton & Garrison before starting her own firm in 2017.