An new report has warned that Amnesty International has had a "toxic" working environment going back as far as the 1990s.
The report into the organisation's workplace culture was commissioned after two staff members from the organisation's International Secretariat in London took their own lives last year.
Undertaken by the KonTerra Group, the Staff Wellbeing Review finds a severe lack of trust in senior management - with bullying and public humiliation routinely used by the organisation's leadership.
It warns that nearly 40% of staff have developed mental or physical health issues as the direct result of working at Amnesty.
"Although Amnesty is an organisation that employs many outstanding, talented, caring individuals; many former and current staff describe Amnesty as an environment in which staff do not feel that they are valued, protected, or treated with respect and dignity," the report states.
"The Assessment Team received many reports - from multiple offices and regions - of power misuse, discrimination, targeting, bullying, and other practices which have undermined wellbeing.
It noted that one staff member said the organisation is a place with “a toxic culture of secrecy and mistrust—a place where there are back-room deals.”
The authors note that "numerous other staff provided similar descriptions."
"Even if you leave aside the unusual occupational stresses that attend exposure to details of human rights violations, this sort of organisational environment has exposed many staff to exceptional levels of stress in recent years," they wrote.
In a statement, Amnesty International Secretary-General Kumi Naidoo said the report "paints a sombre picture of Amnesty International’s recent internal track record."
"To hear our employees speak of a culture of secrecy and mistrust where discrimination, bullying and abuse of power have been condoned is profoundly troubling," he said.
"Unacceptable management practices, attitudes and behaviours cannot and will not be tolerated at any level in the organization."
He said senior management "takes shared responsibility for the climate which emerged where colleagues felt, or continue to feel, undervalued and unsupported - and we are truly sorry."
"But an apology is not enough," he said. "This lesson has been learnt."
"We need to look after each other and develop compassion and mutual care to help Amnesty International become the uplifting community it needs to be."
He noted that "with the increasing pressure on human rights defenders globally, Amnesty International needs to be stronger and more effective than it has ever been, and our resolve and fortitude must start from within."
The report finds that Amnesty's efforts to support staff wellbeing have generally been "ad hoc, reactive and piecemeal," with no comprehensive approach to supporting staff wellbeing.
It finds that organisational culture and management failures are the root cause of most staff wellbeing issues - with the "adversarial culture" of the workplace, failures of management and human resources and pressures related to workload, the biggest contributors to the staff wellbeing issues.
It warns that the organisation's People & Organisational Development department - which combines human resources, recruitment and development - has "largely failed in recent years to fulfil its key roles."