The authorities say up to 200,000 people may flee in the coming weeks, but the government does not expect to have to house them in camps, because most have relatives in the region.
The United Nations High Commissioner for Refugees (UNHCR) said that humanitarian access to people in need remained the key challenge for agencies, given the volatile security environment in the displacement areas.
The UNHCR also reports that in addition to aid given to individual families, assistance will need to be extended to hospitals, schools and other public facilities that may come under strain with large influxes of people.
Arianne Rummery, a spokeswoman for UNHCR told Al Jazeera that, at present, there are about 125,000 refugees to whom gaining access was a key challenge.
"Even the areas that they are going to in Dir Khan and Tank districts, lower down in the North-West Frontier Province, are very volatile from a security point of view.
"People are mainly being hosted by their extended-kin networks in their host communities. The tribal elders are able to use their networks to ensure that people have somebody to stay with.
"So it is not a critical situation where people don't have shelter at the moment. But obviously as the situation goes on these communities will come under more strain."
Aid centre beatings
Earlier on Thursday, baton-wielding police beat back refugees crowding an aid distribution centre run by Pakistani authorities in Paharpur town, about 45km outside Dera Ismail Khan.
"We came here for bread, but the police beat us up," said Rahmatullah Mehsud - one of the injured new arrivals in the town. "There the Taliban were messing with things and the army was showering bombs. Here we have to bear the clubs."
But Javed Shaikh, an aid administrator, said there was plenty of food, but refugees were "impatient".
"There are some policemen deployed who are fed up with the indiscipline of the people," Shaikh said.
Pakistan's offensive is considered a critical test against the Taliban, blamed for attacks inside the country and on Western forces in neighbouring Afghanistan.
More than 170 people across the country have been killed over the past three weeks in a wave of attacks blamed on the Pakistani Taliban.
In the latest attack, Pakistan's police said unknown assailants killed an army brigadier and his driver on Thursday after firing on their military vehicle in the capital, Islamabad.
Qamar Ahmed, an official at the police emergency department, said witnesses saw two men on a motorcycle drive up to Brigadier Moin Haider's vehicle and unleash a hail of bullets at point blank range.
An army statement on Thursday reported two soldiers killed in the South Waziristan operation, bringing the army's death toll to 18, while 24 Taliban fighters were killed on Thursday, bringing to 129 fighters, their death toll during the offensive.