A pedestrian walks past a branch of Oxfam in central London. The charity has been taken to task over ‘a culture of sexual abuse’ involving aid workers in offices overseas. Picture: Simon Dawson / Reuters

LONDON - Reports that Oxfam staff members sexually exploited people in crisis zones are "a stain" that shames the charity, the organisation's chief said in an interview broadcast Friday.

Executive director Winnie Byanyima said she is appointing an independent commission to investigate the allegations that staff members used prostitutes in earthquake-ravaged Haiti and possibly other crisis areas. She urged all victims of abuse to come forward.

"I'm here for all the women who have been abused. I want them to come forward and for justice to be done for them," she told the BBC.

Byanyima said the commission would "look into our culture and our practices" and set up a vetting system for its staff.

U.K.-based Oxfam has been rocked by allegations that senior staff working in Haiti after the country's 2010 earthquake faced misconduct allegations, including using prostitutes and downloading pornography.

Oxfam says it investigated the case, fired four workers and let three others resign, but the British government and charity regulators have criticised its lack of transparency. U.K. International Development Secretary Penny Mordaunt has warned that British government funding to the group — some 31.7 million pounds ($43.8 million) in 2016-17 — is at risk unless it comes clean about the allegations.

South African Nobel laureate Desmond Tutu, British actress Minnie Driver and Senegalese musician Baaba Maal have all quit their posts as Oxfam celebrity ambassadors in the wake of the abuse allegations.

"What happened in Haiti and afterwards is a stain on Oxfam that will shame us for years, and rightly so," Byanyima said.

Associated Press