Two months after the South Asia quake which killed more than 73,000 people, Swiss aid workers are warning of a second wave of deaths as winter sets in.
The Swiss Agency for Development and Cooperation (SDC) says it is racing against time to provide shelter for survivors.
Last week the International Organisation for Migration said that most of the tents being given to some of the 3.5 million people made homeless in northwest Pakistan and Pakistani Kashmir were not designed to cope with harsh winter conditions.
Karl-Friedrich Glombitza, project leader for the Swiss Humanitarian Aid Unit in Pakistan's Mansehra district, told swissinfo that there was an "urgent need" for more temporary-building materials.
"At the moment we are in the middle of distributing to about 10,000 people building materials such as iron sheets, tool sets and energy-saving stoves... so that people can at least survive the winter," he said.
"The problem is that there is a shortage of iron sheets, because production is not sufficient, so we really are witnessing a race... for survival."
According to Glombitza, many quake survivors living in high mountainous areas have not made the journey down to lower-lying regions.
"Quite a lot of people have stayed in the upper areas above 5,000 feet and we are now concentrating mostly on helping them."
The SDC is working together with Pakistan's army, local authorities and other aid agencies to reach those most in need.
The agency has set up coordination centres in the districts of Batagram and Mansehra. It also maintains a permanent logistics office in the capital, Islamabad.
For Glombitza, one of the major logistical challenges facing aid agencies is the fixing of priorities for humanitarian assistance.
He cites the problem of finding a balance between the distribution of food and shelter.
"At the moment I don't see that food shortages are a general problem... and we are frustrated because the [limited] helicopter capacity is being used for food aid while the distribution of shelter kits is a bit reduced," he said.
"I wouldn't say this is a conflict, but there is a need to balance the need for building materials with the need for food. It's more important to transport building materials to people at high altitude.
"If people are not able to stay where they are because they don't have the shelter, there's really no need to send food supplies to these places."
The SDC says the aim should be to allow people to stay as close to their homes as possible.
"Our experience from other earthquakes and areas where there have been wars and conflict is that if you start moving people to tented camps, it's really difficult to integrate them afterwards.
"So the goal should be to keep them [as close to their homes as possible] – which means giving them shelter and then supplies of food."
Glombitza said he was "optimistic" about the chances of survival for the thousands left without homes, but cautioned that the success or failure of the relief effort would depend on the severity of the winter.
The SDC says it is committed to staying in the region and is already preparing "phase two" of its aid programme in the spring, which will focus on rehabilitation.
"We are certainly in this for the long haul," said Glombitza.
swissinfo, Ramsey Zarifeh
The earthquake on October 8 killed at least 73,000 people and left another 3.5 million homeless, most of them in northwestern Pakistan and Pakistani Kashmir.
Hundreds of thousands of survivors are living in tents as winter sets in.
Aid agencies fear the harsh winter could cause a second wave of deaths.
As of November, Switzerland had invested SFr9.6 million ($7.3 million) in emergency aid for Pakistan.
The Swiss Red Cross says it distributed 2,000 tents with ovens, 20,000 blankets and 2,500 field kitchens to the quake area before the onset of winter.