Oxfam's 2011 investigation into the Haiti sex scandal concluded charities should be warned about "problem staff" - only for several accused of abuse to successfully take up future posts in the aid sector.
The charity made the recommendations at the end of a report which detailed four dismissals and three resignations over allegations ranging from the use of prostitutes on charity property to sexual exploitation of employees.
Suspicions that under-age sex workers had been exploited "cannot be ruled out", according to the document.
On Sunday evening Oxfam repeatedly refused to clarify whether it had contacted any of the women allegedly preyed upon, either during or since the investigation.
It has instead vowed to meet with Haitian government more than six years on to apologise for "mistakes" and discuss how to make amends, including to the women affected.
Relief staff had been stationed on the Caribbean island to provide support in the aftermath of an earthquake which killed thousands of people in 2010.
Oxfam officially released the findings of its investigation after a leaked copy was published by The Times, heralding a storm of criticism over how the episode was handled.
It said in a statement: "We are making this exceptional publication because we want to be as transparent as possible about the decisions we made during this particular investigation and in recognition of the breach of trust that has been caused.
"We hope this also contributes to rebuilding trust with those who support our work," it added.
The 10-page report alleges that the director of operations in the country, Roland Van Hauwermeiren, admitted using sex workers in his charity-funded accommodation and was granted a "phased and dignified exit". Last week he denied ever using prostitutes in Haiti.
A section entitled "lessons learned action plan" set out the need for tighter safeguarding across the industry to stop disgraced aid workers moving to new posts.
It read: "Need better mechanisms for informing other regions/affiliates/agencies of behavioural issues with staff when they move and to avoid 'recycling' poor performers/problem staff."
Several men at the centre of the allegations subsequently took up roles in aid organisations, including at Oxfam.
Mr Van Hauwermeiren became a senior figure at Action Against Hunger in Bangladesh - with the charity since claiming Oxfam made no mention of his alleged conduct in 2011.
Similarly, one former staff member was employed by Oxfam as a consultant in Ethiopia just months after being sacked, a move the charity said last week was a "serious error".
Other recommendations included stricter referencing checks for staff, the need for "more embedding of women's rights at the heart of all we do" and a call to refresh and increase awareness training on preventing sexual exploitation and abuse.
Oxfam has been plunged into crisis by details of the investigation becoming public and now faces threatened funding and an investigation by the Charity Commission.
Its report from 2011, however, makes no reference to any direct interaction with the women affected.
The Press Association contracted Oxfam and asked about whether any contact had been made, but the charity refused to comment.
Instead it said in a statement: "Oxfam GB will discuss these cases with the Charity Commission as part of the Charity Commission inquiry to work out what else it can do in relation to the victims.
It added: "The Independent Commission which we announced on Friday will also seek to hear from the women affected."