"I have heard and read many lies… I shall react… Many people, including in the international media, will blush hearing my version of facts," van Hauwermeiren was quoted as saying by the Het Nieuwsblad newspaper.
READ MORE: Oxfam May Lose Millions After Charity Hit by Sexual Misconduct Allegations
Last week, The Times reported, citing its sources, that a number of Oxfam workers, including van Hauwermeiren, had been spending time in their official Haiti residence with prostitutes. On Sunday, the charity was hit with similar allegations saying that Oxfam staff had paid women for sex in Chad in 2006.
The sex scandal has sparked public outrage, primarily due to the fact that Oxfam had conducted an internal investigation into the issue and decided not to make its outcome public, letting its employees leave voluntarily in 2011.
Earlier in the week, Oxfam's Deputy Chief Executive Penny Lawrence said that she was resigning amid the scandal.