MPs are to question senior Oxfam executives later about the sexual misconduct of some of its staff in Haiti following an earthquake in 2010.
Members of the International Development Committee will ask what measures have been taken by Oxfam to prevent exploitation.
They will hear from its chief executive, Mark Goldring, and chair of trustees Caroline Thomson.
Winnie Byanyima the Executive Director Oxfam, who is a Ugandan, will not be among those quizzed.
Oxfam has offered its “humblest apologies” to the Haitian government.
Earlier this month, the Times newspaper published allegations that Oxfam aid workers in Haiti had used prostitutes.
Oxfam, which has almost 10,000 staff working in more than 90 countries, denied a cover-up but its handling of the scandal is being investigated by the Charity Commission.
A redacted version of an internal report from 2011, released on Monday, revealed that three of the men accused of sexual misconduct in Haiti physically threatened witnesses during an investigation.
It also showed:
- One Oxfam employee was dismissed and three resigned for using prostitutes on Oxfam premises. The use of underage prostitutes was not ruled out
- Two more were dismissed for bullying and intimidation – one of whom also downloaded pornography
- Another man was sacked for failing to protect staff
In the report, the charity said director of operations in Haiti, Roland Van Hauwermeiren, “admitted using prostitutes” at his Oxfam residence. Last week, he denied paying prostitutes for sex.
He was granted a “phased and dignified exit” and was allowed to resign, the report added, so long as he fully co-operated with the rest of the 2011 investigation.
It is not known if he was one of the suspects accused of threatening witnesses.
The BBC has discovered that one of the staff dismissed from Oxfam for gross misconduct in Haiti was Raphael Mutiku, a Kenyan aid worker based outside the capital Nairobi.
Asked by a reporter whether he had been with Mr Van Hauwermeiren, Mr Mutiku said “no”. As he got into a vehicle, he was asked why he had been let go by Oxfam but not did not answer.
A source, who was aware of the investigation and was in Haiti at the time, told the BBC that drivers were forced to deliver prostitutes to Oxfam villas.
“They were having parties over there that were described as orgies with a smorgasbord of women, girls, wearing Oxfam T-shirts. It would go on all night.
“We were told they were underage. The security guards, the drivers were talking about it not directly – indirectly – because if they talked to anyone about it they would lose their jobs.”