About 100 Oxfam staff in the UK face redundancy because the charity’s income has fallen since the sexual misconduct scandals were uncovered.
In a statement, Oxfam said the charity was having to reorganise its work to ensure it could "live within our means" after some donors, including the UK government, paused new funding of the charity’s work "pending reassurances".
The statement said: "Sadly, this will mean that we will lose some great people in our international programmes and in the UK. We are still working through the effect this will have on redundancies, but our estimate at the start of the process was that it could affect in the region of 100 staff in the UK.
"We very much appreciate the overwhelming majority of donors of all types who continue to actively support our life-saving work. We look forward to resuming our partnerships with our other supporters as we reassure them that we can meet the high standards they expect of us and to which Oxfam adheres. "
The charity has been the subject of significant criticism in recent months in the media and from government about its handling of sexual misconduct allegations.
The charity is also the subject of a Charity Commission inquiry into its safeguarding practices and its response to claims of sexual misconduct at its Haiti programme in 2011.
In the wake of the claims against the charity, Oxfam voluntarily withdraw from bidding for any new funding from the Department for International Development until it could show it had met the government’s safeguarding standards.
According to the Charity Commission website, Oxfam GB has 4,986 employees.
Nick Owen, regional coordinating officer at the trade union Unite, which represents Oxfam staff, said the charity needed to appoint a chief executive as soon as possible to reassure staff. Mark Goldring made it known this week that he would step down later this year.
"Oxfam workers, many of whom have dedicated their lives to the charity, face losing their jobs through no fault of their own," Owen said. "Staff who remain may well have vastly different roles and responsibilities.
"Given the uncertainty Oxfam is facing, a new chief executive needs to be appointed as swiftly as possible so that they can assess what the charity needs to do to continue to function and take the organisation forward. This will reassure staff that everyone is working on the same page and those making the decision on jobs are dedicated to Oxfam’s long-term future."
Unite is concerned that Oxfam programmes in places including Yemen, South Sudan and Gaza will face closure because of the freeze in government funding to Oxfam.
The union is also calling for international development charities to sign up to a 10-point plan for "cultural change" in the sector.