Oxfam is to make £16m of cuts because of reduced funding in the wake of the Haiti sex scandal.
The charity was accused of covering up claims that staff sexually exploited female victims of the 2010 earthquake.
After the scandal emerged thousands of people stopped making regular donations and the government suspended its funding to the charity.
An Oxfam statement said it was "devastated" that it would have to reduce some of its aid programmes.
However, it said it would target its head offices and support functions to ensure that the majority of its work on the ground could continue.
Claims first emerged in the Times in February that staff, including former country director Roland van Hauwermeiren, used prostitutes while based in Haiti after the earthquake.
According to the paper, Oxfam knew about concerns over the conduct of Mr van Hauwermeiren and another man when they worked in Chad before they were given senior roles in Haiti.
The charity's own investigation in 2011 led to four people being sacked and three others resigning, including Mr van Hauwermeiren.
It produced a public report, which said "serious misconduct" had taken place in Haiti - but did not give details of the allegations.
In February, Oxfam offered its "humblest apologies" to Haiti.
Oxfam GB chief executive Mark Goldring announced his resignation last month, saying that someone else should help "rebuild" the group following the scandal.
Earlier this week it was confirmed that Oxfam GB had been banned from operating in Haiti.
Oxfam GB's annual income last year was £408.6m and it says it spent £303.5m on "charitable activities". - including development and humanitarian projects and campaigning.
Following the announcement of the cuts, an Oxfam spokesperson said: "We are devastated that the appalling behaviour of some former staff in Haiti and shortcomings in how we dealt with that eight years ago means we now have less money to provide clean water, food and other support to people who need it.
"We are immensely grateful to all those - including more than nine in 10 of our regular givers - who have continued to support us during these difficult times.
"We are cutting head office and support functions to ensure that we can continue with the majority of our lifesaving and life changing work on the ground."