NGOs will be unable to help thousands of Iraqis during the initial stages of war, aid agencies have warned.
The Government has refused to provide any extra funding for NGOs to prepare for the consequences of conflict despite its insistence that the motives for war are humanitarian.
Brendan Paddy, senior media officer for emergencies at Save the Children, which operates in the autonomous zone of northern Iraq, said the charity had accepted that it would not be able to make "meaningful preparations".
"Many thousands of people are likely to need assistance almost from the first week or two. This is when agencies will still be organising themselves as the money comes in."
Paddy said that NGOs would receive emergency funding after war broke out but this kind of funding "is too late to save many people and it is less efficient".
"The Government has released billions in extra funding for a possible war to the Ministry of Defence. Given its apparent concern for the people of Iraq, it's surprising that the Government hasn't come up with a single extra penny to help the cash-strapped Department for International Development (DfID) prepare for the humanitarian catastrophe that is likely to follow war," he said.
DfID has given £3.5 million to the UN but despite requests, aid agencies have received nothing to help them prepare.
Save the Children has used its own voluntary income to buy equipment such as clothes and cooking kits for 2,000 children. "This is a monumental achievement in itself but it is a drop in the ocean if there are a large number of refugees," said Paddy.
The charity has also found nutritionists and emergency programme workers but can't employ them until emergency funding starts after conflict breaks out.
A spokeswoman for Care International, which operates in the Iraqi government-controlled area of southern and central Iraq, said: "We are preparing as best we can using our own resources. We have looked for match funding and for private funding but nobody will fork out until they know which way the wind is blowing.
"Given the pace of institutional donors, even if we did get funding, it would be difficult to mobilise."
A spokeswoman for the Treasury said that the only extra funding the Chancellor had announced for preparations for war was £1.75 billion for the Ministry of Defence in February. DfID was the lead department for humanitarian assistance and it was up to it to determine the funding for NGOs, she said.