Oxfam was handed £31.7 million of taxpayer funding in 2016/17.
Several senior officials with the global charity have resigned in the wake of the controversy, including the deputy chief executive of Oxfam Great Britain. "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 and urged all victims of abuse to come forward.
More than 1,000 direct debits to the charity were cancelled over the weekend and Mr Goldring said on Friday that the revelations could have a "substantial effect on public confidence, which would affect public donations".
The aid group said it would create an independent commission which will have the power to access records and interview staff in a bid to stamp out abuse and impose stricter controls on employees.
Oxfam also vowed to quickly publish its 2011 internal investigation into staff involved in sexual and other misconduct in Haiti. The allegations relate to Oxfam Great Britain, one of 20 affiliates that make up Oxfam International.
He also disclosed that one of the men sacked after being accused of using prostitutes was given a job reference from the charity, but it was written by a colleague who was too fired over the allegations.
Speaking to reporters with the Het Nieuwsblad newspaper, who tracked him on the Belgian coast, Van Hauwermeiren said there were "lots of lies and exaggerations" in media reports.
"I'm not a saint, I'm a man of flesh and blood and have made mistakes (not easy to admit)", said van Hauwermeiren, "And I am deeply ashamed".
He said: "I don't think (Oxfam) wanted to promote a sensation and damage the delivery of that programme".
The British charity has faced criticism over the way it handled claims staff hired prostitutes in Haiti in 2011.
Gurpreet Singh worked as a consultant in Ethiopia from October to December 2011, a decision Oxfam said was "a serious error and should never have happened".
At home and overseas, we will not stand for any kind of harassment of staff, partners, volunteers or those we serve and we are doubling the number of people who work on safeguarding to make sure we are living up to our responsibility to protect them.