Actress Minnie Driver has stepped down as one of Oxfam's global ambassadors following revelations of sexual abuse by aid workers in Haiti.
Driver is the first celebrity spokesperson to abandon the charity amid the growing scandal, which includes allegations that Oxfam staff used sex workers in Chad, the CNN said.
"I am nothing short of horrified by the allegations against Oxfam International. In no uncertain terms do I plan to continue my support of this organisation or its leaders.
"And though it is unfortunate that after 20 years I am no longer able to advocate and defend through this specific framework, social and economic injustice is more globally prevalent than ever," she said in a statement on Tuesday.
"I certainly will not let the abhorrent mistakes of a troubling organization stop me or anyone else from working with good people in this space to support a population of human beings around the world that needs our help."
Juan Alberto Fuentes, Chairman of the charity was arrested in Guatemala on Tuesday. He was detained as part of an investigation into a corruption scandal, the BBC reported.
Former Deputy Chief Executive Penny Lawrence also resigned on Monday as the scandal continued to grow.
Oxfam's leaders are accused of trying to cover up the behaviour of some of its senior staff members deployed to Haiti after the devastating 2010 earthquake.
Aid workers, including the Oxfam country director at the time, Roland van Hauwermeiren, were accused of turning a villa rented by the organisation into a makeshift brothel, with prostitutes wearing only Oxfam T-shirts.
Oxfam has apologised for the behaviour of aid workers, but denies a coverup, the CNN said.
Oxfam International Executive Director Winnie Byanyima said the charity is not where it needs to be. But she said it's "much better" than it was in 2011 and it will continue to rebuild.