Cyclone Phailin left a trail of destruction along India's east coast on Sunday and at least seven people dead after the biggest evacuation in the country's history helped minimise casualties.

As emergency teams began assessing damage from the country's biggest cyclone in 14 years, a massive relief effort went into full swing to distribute food to an estimated one million evacuees, clear roads and help the injured.

Most of the local population spent the night huddled in shelters and public buildings as deafening winds flattened flimsy homes, uprooted trees and sent glass and asbestos strips flying through the air.

The worst affected area around the town of Gopalpur in Orissa, where the eye of Phailin packing winds of 200 kilometres an hour (125 miles per hour) came ashore, remained cut off with emergency services rushing to reach there.

Raj Kishor Muduli, a delivery driver who lives just outside Orissa's state capital Bhubaneswar, said the whole of his village had spent the night hunkering down in a communal shelter.

"We were all afraid, the whole village was afraid, we didn't know how strong the winds would be," the 43-year-old told AFP in the morning when the winds had died down and heavy overnight rainfall had ceased.

"Everyone was awake the whole night to see what the size of (the) storm would be and to be on guard."

Pradipta Kumar Mohapatra, Orissa's special relief commissioner, said that seven people were known to have died.

"We can confirm seven deaths in Orissa, mostly due to falling branches from trees," he told AFP in Bhubaneswar.

"Our rescue workers and state officials are working tirelessly to sort things out.

"Electricity and water will be restored everywhere by this evening, except for the district of Ganjam, which has been very badly-affected. We are coming up with a separate plan to address the situation in Ganjam."

More than 8,000 people were killed in 1999 when a cyclone hit the same region, devastating crops and livestock from which the area took years to recover.

This time round, a massive evacuation operation, which officials said was the biggest in Indian history, appeared to have succeeded in minimising casualties.

"I think we have been successful in minimising the loss of precious lives," Orissa's Chief Minister Naveen Patnaik told reporters in Bhubaneswar.

AFP journalists in the cyclone zone said electricity was down in large parts of Orissa and neighbouring Andhra Pradesh while queues formed outside petrol stations with fuel rationed to five litres per vehicle.

High-sided trucks lying on their sides were witness to the strength of the winds on the main highway south of Gopalpur which was littered with uprooted trees and other debris.

But despite the damage, there was a general sense of relief that things could have been a lot worse.

"We were preparing for a super cyclone, but Phailin did not turn into a super cyclone," spokeswoman for the National Disaster Management Authority (NDMA), Tripti Parule, told AFP.

"The last biggest evacuation in India's recorded history was in Andhra Pradesh in 1990 (when another cyclone struck) -- and this is now much bigger."

Officials in Orissa said 860,000 people moved before the cyclone made landfall on Saturday evening, while at least another 100,000 were evacuated further south in the state of Andhra Pradesh. Residents were also evacuated from coastal regions of West Bengal state.

The government had said on Saturday evening that some 550,000 people had been evacuated but efforts to persuade people to flee to safer areas continued until shortly before Phailin made landfall at around 9:00 pm.

Weakening wind speeds

The NDMA's vice chairman Marri Shashidhar Reddy said the cyclone was gradually weakening as it moved in land but winds were still gusting at speeds of up to 120 kilometres an hour.

"Of course, there will be widespread rain all over Orissa and parts of Andhra Pradesh but it may be to the extent of 10-15 centimetres (of rain), slightly lower than what was expected," said Reddy.

Before the storm struck, international weather experts had predicted it would be a "super cyclone", comparable to the 2005 Hurricane Katrina in the United States.

"They have been issuing over-warnings, we have been contradicting them," L.S. Rathore, the director general of the India Meteorological Department (IMD), told a press conference in New Delhi.

"As a scientist there is always a difference of opinion," he added.

But although the worst was over, Rathore said heavy rainfall could be expected to fall in at least five states over the next 24 hours, including in Bihar where floods five years ago killed dozens.

Some of the deadliest storms in history have formed in the Bay of Bengal, including one in 1970 that killed hundreds of thousands of people in modern-day Bangladesh.