London(CNN) British charity Oxfam had a "culture of tolerating poor behavior" among staff sent to help victims of the 2010 Haiti earthquake, and failed to address early warning signs of the sex scandal that rocked the charity sector last year, a new report has found.
Oxfam's mismanagement in Haiti prompted the UK regulator, the Charity Commission for England and Wales, to issue an official warning to the organization in a damning report released Tuesday.
It found that allegations from 2011 of "serious problems with the culture, morale and behaviors generally" of some staff were not properly addressed, with senior members failing to escalate complaints of sexual misconduct.
In one case, the commission said senior staff at Oxfam received emails said to be from a 12- and a 13-year-old girl alleging abuse by employees in Haiti, which the charity suspected were not genuine. While the report "found no record that there was a 'cover up,'" it concluded that the allegations were not adequately investigated, despite the suspicion that the allegations were false.
The report is part of an 18-month investigation into Oxfam's handling of the scandal, finding that the charity "missed opportunities" to address "cultural and behavioral issues" of staff in Haiti at that time.
It follows explosive allegations last year that some staff, including the Haiti country director, hired prostitutes at Oxfam properties while working in the country after the devastating earthquake.
The allegations first emerged in 2011, prompting an internal investigation, but Oxfam didn't make them public until 2018.
According to the report at the time, four staff members were dismissed for "gross misconduct" and three others resigned after the investigation, including country director Roland van Hauwermeiren.
This week's inquiry by the charity regulator found that Oxfam's response to the scandal was inadequate. It said that after the company's "internal investigation into staff misconduct in Haiti," the "limited actions taken to address the issues raised" were "not sufficient."
And "by that stage staff confidence in Oxfam GB to address the behavior of some staff in Haiti had further eroded," according to the report.
On Tuesday Oxfam said in a statement it accepted the findings of the commission, and was "deeply sorry for its failure to prevent sexual abuse by its former staff in Haiti."
"What happened in Haiti was shameful," said Caroline Thomson, the charity's chair of trustees, in a lengthy statement. "It was a terrible abuse of power, and an affront to the values that Oxfam holds dear."
"The decision to allow the Country Director to resign without a fuller investigation of his own conduct would not be permitted today, under our current policies and practices. And while the commission makes clear that it found no record of a 'cover-up,' we accept that Oxfam GB should have been fuller and franker in its initial reporting of the allegations."
The inquiry comes as the British aid sector emerges from a series of damning reports into sex abuse by workers, with a UK government inquiry last year finding that such abuse was "endemic" and has been happening for years.