Rescuers recovered scores of bodies from the Ganges river in northern India Friday, as the death toll from flash floods and landslides neared 600, with thousands of mainly pilgrims and tourists still stranded or missing.

Dozens of helicopters and thousands of soldiers have been deployed to rescue more than 35,000 trapped people, the home ministry said, almost one week after floods and landslides from torrential monsoon rains struck the Himalayan state of Uttarakhand.

Raging rivers have swept away houses, buildings and entire villages, and destroyed bridges and narrow roads leading to pilgrimage towns in the mountainous state, which is known as the "Land of the Gods" for its revered Hindu shrines.

"556 bodies have been noticed by the army... either floating or buried in slush," Vijay Bahuguna, state chief minister told local TV channel CNN-IBN on Friday evening.

Scores of bodies were recovered from the Ganges river earlier Friday, with the death toll expected to rise further as flood waters recede to reveal the extent of the devastation, and rescue workers reach more isolated areas.

"This kind of disaster has never happened in Himalayan history," Bahuguna said.

He attacked the India Meterological Department (IMD) for not issuing adequate warning ahead of the heavy rains, which struck earlier than expected, saying the local government was unable to prepare for the deluge and evacuate people on time.

"The IMD warning was not clear enough," he said, adding that it would take another 15 days to evacuate all the tourists.

Anxious relatives waited at state capital Dehradun, where military helicopters and other aircraft were assisting with rescue efforts.

Neelam Rana, a 27-year-old mother of two, who was rescued with her family on Friday after waiting nearly a week for help said she was "overwhelmed" to finally leave.

"We suffered a lot. Our food ran out, I don't know how we survived," she told AFP, as she prepared to leave with her husband and children, aged two and five.

Distraught relatives clutching photographs of missing family members were waiting outside Dehradun airport for news.

Amit Thakur, 40, said his 11-year-old nephew had been missing since their family-run hotel collapsed last week.

"I just hope the army will trace our little boy. I have been standing outside the airport for the last three days to get any information about him," Thakur told AFP.

Uttarakhand's relief minister Yashpal Arya told AFP earlier Friday that with so many missing "the numbers of the dead could rise sharply in the days to come".

The military operation, involving some 43 helicopters and more than 10,000 soldiers, was focussed on reaching those stranded in the holy town of Badrinath after earlier finding widespread devastation in the Kedarnath temple area.

Home ministry spokesman, Kuldeep Singh Dhatwalia told AFP late Friday: "Our soldiers have rescued more than 50,000 people, including around 16,000 people who were evacuated today."

A private helicopter carrying aid crashed earlier on Friday, wounding the pilot, the Press Trust of India reported, in an incident which highlighted the difficulty of reaching rain-deluged areas.

Another 17 people have been killed in the neighbouring state of Himachal Pradesh, a senior government official said.

Floods and landslides from monsoon rains have also struck bordering Nepal, leaving at least 39 people dead, the Nepalese government said.

Some of those stranded in mountainous areas of Uttarakhand were trying to walk to safer ground. Pictures showed pilgrims, aided by soldiers, using ropes and makeshift ladders to climb down cliffs and cross rivers.

Soldiers have also reached some of the villages in lower-lying areas by boat, ferrying women clutching babies, children and elderly men to safety. Video footage showed only roofs of houses visible above the water line.

Rescue workers who have managed to reach those stranded are racing to cut down trees and clear vegetation to allow military helicopters to land and evacuate those most in need, a state official said.

"Thousands of tourists are waiting in the dense forests. They had all taken refuge in the jungle after hotels and other buildings collapsed," the state's principal secretary Rakesh Sharma said.

"We are trying all possible ways to rescue them. Roads are totally destroyed."

Prime Minister Manmohan Singh late on Thursday announced a $170 million aid package and an online appeal for funds, asking "all citizens of India to stand with our distressed fellow countrymen" and "donate generously".