The United Nations has estimated that Rohingya Muslim refugees in Bangladesh will need $200 million (£148 million) during the next six months.
The refugees have fled from Myanmar due to violence against them in the country which the UN has called ethnic cleansing, according to Reuters.
Since the middle of August, 422,000 Rohingya people have arrived in Bangladesh but both the Bangladeshi authorities and foreign aid organisations are finding it difficult to help them.
Before this there were already roughly 400,000 Rohingya Muslims in the country who had fled previous violence.
Those sending aid are also running into problems in Bangladesh such as monsoon rains flooding roads.
The UN resident coordinator in Bangladesh Robert D Watkins told Reuters "right now, we’re looking at $200 million" although this has not yet been confirmed.
"It is a ballpark figure based on the estimates on the information we have" Watkins said, dding "we base these appeals on immediate needs, and right now we know they’re going to be [in Bangladesh] for six months.”
However, Myanmar has claimed ethnic cleansing is not taking place in the country and violence is due to fights between security forces and insurgents from the Arakan Rohingya Salvation Army.
Watkins also said the UN doesn't want to plan a 10-year operation as it is hoped a negotiation will take place so refugees can return home.
He added: ”We can’t plan too far in the future because it becomes a self-fulfilling prophecy. On the one hand, politically, it sends a strong signal, which we don’t want to send, which is that people are going to be here for a long time."
This week the leader of Myanmar, Aung San Suu Kyi, said the country would start allowing refugees in Bangladesh to return, if their status is verified. However many do not have official papers showing their place of residence.