The government has set up camps, but a vast majority of the estimated two millions of displaced people are staying with relatives or in private accommodation.
Hillary Clinton, the US secretary of state, pledged $110m in humanitarian aid to Pakistan on Tuesday as part of Washington's new strategy for helping Islamabad counter the Taliban.
The funds would be used to deliver tents, FM radios, meat, water lorries, generators and other supplies, Clinton said.
Some of the money would also be spent on buying Pakistani wheat to boost the local economy.
'Humanitarian catastrophe'
Al Jazeera's Kamal Hyder, reporting from Islamabad, said the amount of aid was not near to what Pakistan needs as fighting between government forces and the Taliban appears to be spreading.
"People from Matta, who had endured weeks of curfews, are now escaping over the mountains. Families are being separated from each other and it's another humanitarian catastrophe unfolding there," he said.
"If the government offensive will be extended, it will become a very serious issue to contain.
"However, as far as the military is concerned, it has to first clear Swat.
"It has already cleared Buner [district bordering Swat] and that would allow the people of Buner to go back.
"But it has a big fight on its hands in Swat and what happens [there] will determine what happens in Waziristan as well."
Asif Ali Zardari, the president, told Britain's Sunday Times newspaper during the weekend that the military offensive could be expanded.
"We're going to go into Waziristan, all these regions, with army operations," the paper quoted the president as saying.
"Swat is just the start. It's a larger war to fight."
Our correspondent said the number of displaced is expected to increase, as thousands of people reportedly are leaving the Mehsud area in South Waziristan.
"They are not being helped entirely by the government. The people of this country are going out of their way to give them some kind of shelter."
'Horrible speed'
President Zardari convened a meeting of government and UN officials on Wednesday on relief and rehabilitation efforts.
Yousuf Raza Gilani, the prime minister, said Pakistan was fighting the Taliban on two fronts - in the mountains and in trying to cope with the humanitarian crisis.
Rashid Khalikov, director of the United Nations' humanitarian office in New York, has said that aid workers are struggling to reach many of those who fled as the number of displaced increased with "absolutely horrible speed."
The UN estimates that about 1.4 million people have been displaced since fighting in Pakistan's Northwest Frontier Province (NWFP) started at the end of April.
That estimate is in addition to about 550,000 people already displaced by fighting across the NWFP and in other Pakistani regions.
John Holmes, the UN humanitarian chief, said only about 20 per cent of displaced civilians are inside about 24 refugee camps at the moment.
Pakistan's military has said up to 15,000 troops are fighting 4,000 well-armed Taliban in Swat.