Oxfam is to make £16m worth of cuts after donors abandoned the charity in the wake of a sexual misconduct scandal.
An internal document seen by The Guardian told staff that the charity has to make savings in order to get on a "more stable and sustainable footing".
Job losses will be "inevitable", according to the letter from chief executive Mark Goldring. Some town centre charity shops could be sold off.
In a statement sent to City A.M. by Oxfam, the charity said it would cut head office and support functions to ensure most aid work would not be affected.
But it is understood that one option could involve reducing the number of countries in which Oxfam operates.
The £16m figure represents about 10 per cent of the charity's unrestricted income, which is the money raised from individuals and shops which it can use at its own discretion.
Goldring is set to stand down at the end of this year, but has committed to dealing with the fallout of the scandal.
The organisation is facing an inquiry by the Charity Commission, over allegations it failed to disclose details of alleged sexual misconduct by staff in Haiti.
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."