Rescue workers stepped up the search for bodies Thursday in India's flood-ravaged north and mass cremations took place as fears grew over outbreaks of disease, officials and reports said.

More than 100,000 mainly pilgrims and tourists have been evacuated from the disaster zone while some 4,000 remain in relief camps after the flash floods and landslides that hit the state of Uttarakhand on June 15.

Rivers swollen by monsoon rains have swept away houses, buildings and entire villages in the Himalayan state, which was packed with tourists and pilgrims travelling to Hindu shrines.

Around 1,000 people have died, the state government has told AFP, although officials have warned the death toll could rise as more victims are found.

Persistent bad weather is hampering evacuations from the relief camps, officials said, and their focus is increasingly on recovering bodies to prevent the spread of disease.

"The remaining people will be evacuated as and when the weather clears," a senior officer overseeing rescue operations told AFP.

"The bigger worry is finding the scores of dead bodies that may be still buried under debris," said the officer, who did not want to be named as he is not authorised to speak to the media.

Health officials have warned locals against drinking river water on concerns of contamination from rotting bodies.

Six bodies were found floating in the Ganges in Allahabad on Wednesday, some 650 kilometres (404 miles) downstream from Kedarnath, according to reports, highlighting the difficulty of locating all those who perished.

Rescue workers are clearing away large amounts of debris and scouring remote areas for victims. More than 1,000 bridges have been damaged along with roads, cutting off villages and towns.

A team of police, doctors and firemen has been deployed to the worst-hit Hindu temple area of Kedarnath Valley to recover bodies there, the officer said from the state capital Dehradun.

All survivors in that area have already been picked up.

"They are carrying saws, plate-cutters and also saline water which is needed to preserve body parts," the officer said.

The team includes mountaineers to retrieve bodies found in the jungle, valleys and gorges, and help carry them out on foot, as well as photographers who will send pictures to the police to speed up the identification process.

Mass cremations of victims were under way in the Kedarnath area, to prevent outbreaks of disease, said Ravikanth Raman, a rescue operations officer in Guptkashi, a village near Kedarnath.

"We are now quickly cremating the bodies which have been recovered," Raman told the Press Trust of India news agency.

"But given the scale and nature of the tragedy, there is a likelihood that many bodies could still be lying in open spots, where rescue personnel have not been able to find or reach them," he said.

DNA samples from the bodies are being taken before cremation and are being preserved by the authorities, officials said.

The search for bodies and the cremations came as villagers accused authorities of ignoring the needs of local residents and instead focusing rescue and relief efforts on visiting pilgrims and tourists.

"There were 67 houses in our Chandrapuri village out of which 63 were washed away by the Mandikini river," Birendra Singh, a former army officer, told AFP at a relief camp in Dehradun.

"Not a single official has visited our village as yet. We have nothing to go back to," he said.