The Government is reviewing its relationship with Oxfam amid growing criticism of the charity's handling of sexual misconduct allegations against some of its staff.
The Department for International Development (DfID) took the decision after the charity denied claims it had covered up the use of prostitutes by aid workers in Haiti in 2011.
Oxfam said it publicly announced an investigation into the allegations when they surfaced and kept the Charity Commission informed.
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 Charity Commission said it was made aware of an ongoing internal investigation into misconduct in August 2011.
It said: "It explained that the misconduct related to inappropriate sexual behaviour, bullying, harassment and the intimidation of staff.
"The report to us stated there had been no allegations, or evidence, of any abuse of beneficiaries. It also made no mention of any potential sexual crimes involving minors."
The Commission said it had written to Oxfam "as a matter of urgency" to request further information and "establish greater clarity on this matter".
Oxfam said allegations that under age girls may have been involved were not proven.
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.
"We often work with organisations in chaotic and difficult circumstances," a DfID spokesman said.
"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.
"We acknowledge that hundreds of Oxfam staff have done no wrong and work tirelessly for the people they serve, but the handling by the senior team about this investigation and their openness with us and the Charity Commission showed a lack of judgment.
"We have a zero tolerance policy for the type of activity that took place in this instance, and we expect our partners to as well.
"The Secretary of State is reviewing our current work with Oxfam and has requested a meeting with the senior team at the earliest opportunity."
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."
He added that any references given to staff involved in the scandal, who later found other jobs, had not been officially sanctioned.
Oxfam added in a statement: "With up to 10,000 NGOs working in Haiti alone in 2011, not to mention hundreds of thousands of aid workers in countries around the world, it was unfortunately not possible for Oxfam to ensure that those found guilty of sexual misconduct were not re-employed in the sector.
"Oxfam has not and would not provide a positive reference for any of those that were dismissed or resigned as a result of the case."