Oxfam has withdrawn bids for UK government funding while it investigates its handling of the Haiti sex scandal - as it received a new warning public money could be taken away from it.
International Development Secretary Penny Mordaunt said she had set a deadline of 26 February for all the government's charitable partners to deliver assurances on their safeguarding and reporting practices.
She said: "The UK Government reserves the right to take whatever decisions about present or future funding to Oxfam, and any other organisation, that we deem necessary."
Oxfam's international director Winnie Byanyima earlier apologised for the charity's response to the 2011 scandal and urged victims of abuse by aid workers to come forward.
Ms Mordaunt said in a statement Oxfam had confirmed it would comply with three demands she had made of the charity:
they will make clear how they will handle any forthcoming allegations around safeguarding - historic or live
they will report staff members involved in this incident to their respective national governments
they will fully cooperate with the Haitian authorities, including handing over all evidence they hold.
Ms Mordaunt added: "Oxfam has agreed to withdraw from bidding for any new UK Government funding until DFID is satisfied that they can meet the high standards we expect of our partners."
Amid fears charitable causes will be harmed by a reduction in funds, she said: "In taking these actions I am very aware that there are hundreds of good, brave and compassionate people working for Oxfam around the world. They have been poorly served by Oxfam’s leadership team too."
Oxfam global chief sorry 'from the bottom of her heart'
International director Winnie Byanyima asked for forgiveness for the charity "from the bottom" of her heart and confirmed new measures will be taken to target any sexual misconduct within organisation.
These include the appointment of a high-level commissioner to look into Oxfam's "culture and practices".
This figure would be mandated to examine past cases of misconduct and Oxfam's response.
Ms Byanyima said measures would also be taken to ensure offenders would not be able to falsify references from the charity.
Plans are also in place to double resourcing for safeguarding and make Oxfam's whistleblowing process "safe and confidential".
It comes as further allegations emerge against the scandal-hit charity:
Oxfam has been blighted with allegations that its aid workers used Haitian prostitutes following the country's 2010 earthquake and that the organisation tried covering it up.
A former Ugandan MP, Ms Byanyima spoke in her own language to convey how sorry the charity was over the affair.
"I have two priorities now," she said.
"One is to make sure that the work we do as Oxfam - of saving lives and reaching vulnerable people - continues, because it is vital.
"My second is to route out sexual misconduct from our organisation."
"I'm really inviting anyone who has been a victim of abuse by anyone in our organisation to come forward," Ms Byanyima.
"I'm here for all the women who have been abused. I want them to come forward and for justice to be done for them."