The UN has appealed for a total of $543m (€389m) to help 1.7m people displaced by the ongoing military offensive in northwest Pakistan.
The appeal comes as people continue to stream out of the conflict zone into camps set up in different parts of the North West Frontier Province.
A UN statement said the figure included $88.5m, which had already been provided or committed by donors, but aid agencies and non-governmental organisations need $454.6m in extra funds urgently to help the internally displaced.
The money is also needed to provide continuing support to 550,000 people who have fled the situation since August last year.
UN agencies and Pakistani and international relief groups were 'working together to ensure we get relief to people as quickly as possible', the statement said.
Pakistan's economic affairs minister Hina Rabbani Khar said Islamabad backed the humanitarian appeal.
Diplomats based in Islamabad have expressed concern over the situation in Swat and said their home governments were actively considering further aid in response to the latest UN appeal.
As the conflict ploughs on with no end in sight, concerns are mounting about how to cope with the displaced, uprooted in what rights groups have called Pakistan's biggest movement of people since partition from India in 1947.
Western countries have already separately pledged $224m of aid including $100m from the US.
