The Government is reviewing its relationship with Oxfam in the wake of sex allegations against some of the charity's staff.
Oxfam has denied it covered up the use of prostitutes by aid workers in Haiti in the aftermath of the 2010 earthquake.
The charity said it had publicly announced an investigation into the allegations when they surfaced seven years ago.
But the charity regulator said Oxfam's report stated there had been no allegations of abuse of beneficiaries and did not mention potential sexual crimes involving minors.
"Our approach to this matter would have been different had the full details that have been reported been disclosed to us at the time," the Charity Commission said in a statement.
Four members of staff were dismissed and three, including the country director, resigned before the end of the 2011 investigation, Oxfam said.
The review comes amid fresh reports in The Times that Oxfam did not tell other aid agencies about the behaviour of staff involved in the investigation after they left to work elsewhere.
DfID said Oxfam had "serious questions" to answer following the revelations.
A DfID spokesman said: "We often work with organisations in chaotic and difficult circumstances.
"If wrongdoing, abuse, fraud, or criminal activity occur we need to know about it immediately, in full.
"The way this appalling abuse of vulnerable people was dealt with raises serious questions that Oxfam must answer."
Oxfam chief executive Mark Goldring earlier denied suggestions of a cover-up.
He told BBC Radio 4's Today programme: "With hindsight, I would much prefer that we had talked about sexual misconduct, but I don't think it was in anyone's best interest to be describing the details of the behaviour in a way that was actually going to draw extreme attention to it."