About 7,000 people have stopped making regular donations to Oxfam since it emerged some of its staff used prostitutes in Haiti, MPs have heard.
Oxfam boss Mark Goldring apologised to the International Development Committee for the damage done to people in Haiti and the wider efforts of aid workers.
He said 26 fresh allegations had been made since the scandal broke.
Mr Goldring also apologised for remarks made about murdering babies in cots, which he made when defending Oxfam.
In an interview with the Guardian last week, he said: “The intensity and ferocity of the attack makes you wonder, what did we do? We murdered babies in their cots?”
Mr Goldring, who joined the charity as chief executive in 2013, said he was “deeply sorry” for the comments that he had made while “under stress”.