Cafod said it was “unaware” of the claims until they were contacted by the Times, which broke the Oxfam story.
Meanwhile, charity Doctors Without Borders said it had handled 24 cases of harassment or sexual abuse last year.
In a statement Cafod, an international development charity, said that when the employee had applied for the job in 2014, it had received two references, including one from Oxfam, but that it was not told of the allegations.
Earlier this week, when Cafod became aware of the issue, the staff member was put on leave while the charity investigated.
In its statement Cafod said it was “committed to a zero-tolerance approach to misconduct” and the employee’s failure to disclose the circumstances of his departure from Oxfam were in breach of its code of behaviour.
It added that it has not received any complaints about the employee during his tenure.
The charity has now also reviewed two historical cases of sexual misconduct allegations against other employees. One yielded no evidence and one saw a staff member dismissed.