Aid workers in Kashmir say winter weather and untreated injuries could cause another wave of deaths in the earthquake-hit region.
Doctors in Pakistan-administered Kashmir say tens of thousands of people across the state are still waiting to receive treatment.
As many as 54,000 people may have died in the quake, local officials now say.
Many of the survivors are in remote mountains or deep valleys with no medical help available.
The United Nations says more than three million people have been left homeless and the Pakistani government says it needs another half-a-million tents capable of withstanding winter conditions.
One UN official in Pakistan says the deep valleys and high mountains of Kashmir are less accessible for relief workers that the area affected by the 2003 Bam earthquake in Iran or the coastal regions devastated in last year's tsunami.
"Here we've got over 15,000 villages spread out through the affected region," Andrew Mcleod, operations manager of the UN Emergency Response Team working out of Islamabad, told the BBC.
"The affected areas are much larger in geographical size than the tsunami, and rather than being in flat coastal areas, we are operating in some of the highest mountains and deepest valleys in the world."
Amputations
The medical situation in some of the remote areas is being described as tragic by one aid official, with many of the injured facing death unless they receive immediate medical attention.
Sebastian Novak of the International Committee of the Red Cross flew by helicopter to reach the remote village of Chaka, which had not been previously reached.
He told the BBC that 25% of the patients have had their limbs amputated.
"I had a young lady today, she was about 20, both legs amputated at the knee, and her right arm off, so she basically only had her left arm left.
"There are children amputated, old people amputated. Everybody is going straight to amputation," he said.
Helicopter row
Improved weather on Tuesday has meant that helicopters have resumed operations in Pakistan-administered Kashmir.
Soldiers used mules to reach victims living in steep villages along some of the region's remote valleys.
But aid agencies and correspondents say the need for more helicopters remains the most urgent priority in Pakistan-administered Kashmir.
On Monday, India and Pakistan failed to agree terms under which Indian army aircraft would join the search-and-rescue mission to reach earthquake survivors.
Pakistan says it will accept Indian helicopters but not crew, while India insists its pilots must fly the craft.
India has suggested it will allow Pakistani aircraft to carry out relief operations on its side of the Line of Control in Kashmir, and offered to work on the Pakistani side.
Islamabad said it was unacceptable for Indian military personnel to be operating in Pakistani-administered Kashmir.
The BBC's Aamer Ahmed Khan in Karachi says an agreement between the historic rivals could potentially double the size of the fleet of relief helicopters operating in Pakistan and Pakistan-administered Kashmir.
Pakistan's government puts the overall number of deaths in Pakistan-administered Kashmir and North West Frontier Province at about 40,000.
In Indian-administered Kashmir, officials say 1,400 people were killed.
PHOTO CAPTION
A Kashmiri earthquake survivor collects clothes for her family in Muzaffarabad, capital of Pakistan-administered Kashmir October 18, 2005. (REUTERS)