"With all responsibility, I can say that not less than 40,000 are killed," Sikandar Hayat Khan, the prime minister of the Pakistani side of the divided Himalayan region, said on Sunday.
"There are still cities which are not cleared of debris and the death toll could go to 70,000 or 80,000. It is the worst tragedy in our history," he said.
It was a drastic jump from the last government figures that said more than 25,000 people died in Pakistani-administered Kashmir from the powerful 8 October earthquake.
Pakistan's central government had earlier said that more than 13,000 people were killed in the North West Frontier Province.
The earthquake also ravaged the Indian side of divided Kashmir, killing 1329 people there, according to Indian police.
Line of Control
The Pakistani Kashmir leader said many of the freshly reported casualties were near the Line of Control, the ceasefire line that is the de facto border in the bitterly disputed Himalayan region.
Many new casualties were near
Kashmir's Line of Control
"Some areas along the Line of Control and the areas where the snow is falling ... there is still debris. Helicopters have not reached there," he said.
But he said the military was doing its best in conditions that some relief workers have said are the most difficult they have ever encountered in a natural disaster.
"We have not been able to clear the debris. But the army is doing its maximum. They are picking out the areas. They are providing relief and help to the affected people," he said.
But relief workers have warned that thousands of people risk death within days unless help, particularly tents to shield from the imminent winter, comes immediately.
Nearly all helicopters were grounded on Sunday on both sides of Kashmir because of heavy rain and clouds.
A growing number of political leaders in the two sectors of Kashmir have called for an unprecedented opening of the Line of Control to speed up relief operations for the catastrophe.
Relief workers say thousands of
people risk death within days
So far, four countries - the United States, Germany, Japan and impoverished neighbour Afghanistan - have responded to Pakistan's request for helicopters but the Japanese aircraft are not yet in operation, officials said.
Some 3.3 million people have been left homeless in Pakistan, and officials and aid agencies warn that many will not receive help before winter closes in on the rugged Himalayan region and leaves mountain villages stranded.
"It's a logistical nightmare," said Alain Pasche, coordinator of UN relief operations in Muzaffarabad, the ravaged capital of Pakistani-administered Kashmir.
"Especially so in the little villages and for the people who are coming into Muzaffarabad. The situation is catastrophic here," he said.