Washington: Threat to quit is looming large on the director of UNAids, Michel Sidibé, for his handling of a recent sexual assault investigation.

Three South African civil society groups have called for an independent inquiry into the agency’s leadership, while the Aids Healthcare Foundation has written to António Guterres, the UN’s secretary general, calling for Sidibé to stand down. The AFH is a non-profit organisation that provides HIV care to hundreds of thousands of people globally.

Professor François Venter, deputy director of the Wits Reproductive Health and HIV Institute, has also resigned from a UNAids advisory committee in protest at its “deeply disturbing and tone-deaf” response to criticism.

Treatment Action Campaign, Section27 and Sonke Gender Justice said in a statement that they were concerned by Sidibé’s apparent interference during a recent inquiry into allegations against his deputy executive director, Luiz Loures, and at disparaging comments he has made about women who have spoken out publicly.

One former employee, who left in 2015, said: “I had an exit interview with Michel when I left and the first words out of my mouth were, ‘Your deputy director is a sexual predator and everybody knows it. I’m telling you because you really have to do something about it.’”

Brostrom alleges Sidibé attempted to bribe her to drop her complaint by offering a promotion. Sidibé denies the claim, but admitted to WHO investigators that he had met with Brostrom to suggest they “see how we can really find a way out without making it a big problem for all the organisation and for the credibility of the organisation, for yourself”.

In an official report, investigators said they were perplexed by Sidibé’s attempt to resolve the matter informally, given that he knew the case was under formal investigation.

The director added: “We know there are people taking their golden handshake from us here and knowing that they have a job and then attacking us. We know all about that. We know every single thing. Time will come for everything. When I hear anything about abuse of our assets, abuse of our things, I ask for investigation. Maybe these investigations are going on.”

TAC, Section27 and Sonke Gender Justice said they “consider such victim blaming to be completely unacceptable”.

They added there should be “a detailed investigation into Sidibé’s role in the investigation, his communications with Brostrom, and his communications with UNAids staff and with the media”. A report of such an investigation must be made public, it added.

In an email announcing his resignation from UNAids scientific and technical advisory committee, Prof Venter said: “The fact that there is a pattern of harassment, bullying public statements to staff, delayed investigations and apparent conflict of interest in the investigation, suggests that women working at UNAids are facing an unacceptably hostile working environment.”

AHF, which works in 39 countries, said Sidibé has damaged UNAids’ reputation and is incapable of leading it. Calling for his resignation, it added there should be “an independent investigation and evaluation of whistleblower and sexual harassment practices and procedures, and their strengthening across the entire UN system”.

The letter continued: “Unless UNAids undergoes a comprehensive restructuring and leadership transition, it should be disbanded and its responsibilities transferred to the World Health Organization … Placating civil society with consultations will not make this problem go away.”

In response to previous criticism, UNAids said it has a zero tolerance policy for sexual harassment, with clear guidelines and procedures to address allegations and complaints. The agency said the recent investigation into Loures was carried out by the WHO’s Office of Internal Oversight Services and followed correct procedure.

UNAids has also launched a five-point plan to tackle sexual harassment. This includes initiatives such as introducing focal points in each department, an open platform to report harassment, better training, and an enhanced performance management system.