On Wednesday the toll nearly doubled as it rose to 7,616 from 4,000 on Tuesday.

But an official in the worst-affected area, Ersama, said there could be as many as 4,000 more bodies still lying in the waterlogged fields.

Ersama town: 1,500 bodies found nearby

Ersama was hit both by the cyclone and its tidal surge. Many had nothing but falling trees to cling to.

Shocked survivors talked of the sea taking bodies back with it.

One official said most of the bodies being recovered were "in a highly decomposed condition".

"In Ersama [county], 10 villages were completely wiped out and there was not a single survivor," he added.

The BBC's Mike Wooldridge in Orissa: "The task remains a huge one"

A spokesman for an army contingent which reached Ersama on Tuesday said the sight in the county was horrific beyond description.

State relief commissioner DN Padhi said 6,383 of the known dead were from Jagatsinghpur and warned the toll was ''bound to go up even higher".

Cremations

Orissa state officials have stepped up efforts to cremate the rotting bodies and animal carcasses which are poisoning the water supply.

There has already been an acute outbreak of gastro-enteritis, and there are fears of typhoid and malaria epidemics.

Relief workers wearing masks are trying to dispose of the decomposing corpses as fast as possible to prevent the spread of disease. But it is a gruesome task.

"Predators are feeding on the carcasses, and the dead bodies are making things worse," said Ersama resident Jiban Padhi.

The BBC's Mike Wooldridge: "Officials said there were several thousand bodies lying in the fields"

"There is no more mass cremation. Whenever we see a body, we immediately cremate it. There is no time to do the cremation in a systematic way."

Plans for mass cremations have also been hampered by a shortage of wood.

State officials are now using the air force to drop volunteers equipped with kerosene to burn bodies where they are found.

Gastro-enteritis

For the survivors, there is the danger of disease. Health Secretary Meena Gupta reported 29 deaths from gastro-enteritis on Wednesday, saying 3,000 people were suffering from the water-borne disease.

Rotting bodies likely to cause epidemics

Non-governmental relief workers believe at least 100,000 people are sick with gastro-enteritis and cholera symptoms.

But Ms Gupta dismissed the estimates. She said there were no epidemics and large stocks of medicines were now available.

With water levels receding, relief helicopters were able to start landing for the first time on Tuesday to distribute food, medicines and airlift out some of the sick.

Officials said rescue workers had finally cleared the roads to every marooned village and had disinfected most drinking water wells.

Homeless

The storm, which has left some 10 million homeless, swept in from the Bay of Bengal on 29 October with winds of up to 300km (190 miles) per hour.

The government in Orissa has been accused of not responding fast enough to the disaster.

Millions of people have lost their crops, their homes and access to clean water and health services. Reports say about 175,000 cattle perished in the cyclone.

The United Nations says the gravity of the situation cannot be overestimated.