International development secretary Penny Mordaunt meeting with chiefs of Oxfam today, after the scandal embroiling the charity over the weekend spread to include some of the biggest groups in the UK.
Save the Children, British Red Cross and Christian Aid have all confirmed that they had investigated their own sexual harassment or sexual misconduct cases in the last year.
It follows the revelation that Oxfam covered up the use of prostitutes by its aid workers in Haiti, following the 2011 earthquake. One of those named in the scandal was country director Roland Van Hauwermeiren, who The Times alleges used prostitutes at a villa rented for him by the charity.
According to the Sunday Times, more than 120 charity workers were accused of sexual abuse last year.
Save the Children investigated 31 cases of sexual harassment last year, with 16 people being fired and 10 being referred to police or other authorities as a result. None of the cases involved children.
The British Red Cross confirmed there were a "small number" of sexual harassment cases last year in the UK and "appropriate (action) was taken".
Christian Aid said it investigated two sexual misconduct cases in the last year, which led to it sacking one worker and carrying out disciplinary action against another.
Mordaunt has already warned Oxfam it faced losing all its government funding - which last year was just shy of £32m - if it did not show "moral leadership".
She is meeting with Oxfam officials to discuss the scandal today and has written to all UK charities which receive UK aid to tell them they must declare all "safeguarding concerns" or lose funding.
Mordaunt said: “My absolute priority is to keep the world’s poorest and most vulnerable people safe from harm. In the 21st century, it is utterly despicable that sexual exploitation and abuse continues to exist in the aid sector.
"The horrific behaviour by some members of Oxfam staff in Haiti in 2011 is an example of a wider issue on which Dfid is already taking action, both at home and with the international community via the UN."
However Mordaunt's predecessor Priti Patel claims she raised this issue with Dfid and the Charity Commission, saying she received "pushback" when she did so.
Last autumn, Patel gave a speech to the UN in which she stated she had seen "child rape, sexual exploitation and abuse carried out under the UN flag – and not just by peacekeepers or in peace operations".
At the time she called for full transparency "about any and all accusations made against their staff, contractors and implementing partners", saying: "Any agency that receives funds from us must have the strongest possible measures in place to protect vulnerable populations, especially children, and to deter, detect and catch paedophiles and sex offenders."
She added: "This is a defining moral issue for the UN and for Member States and there can be no more excuses."