A massive relief operation kicked into gear in eastern India Sunday after a terrifying cyclone killed at least 18 people, forced one million from their homes and left a trail of destruction along the coast.

Cyclone Phailin was dissipating rapidly after pounding the states of Orissa and Andhra Pradesh overnight, uprooting trees, overturning trucks, flattening homes and knocking out power lines.

Casualties were minimised after the biggest evacuation in the country's history saw some one million people huddle in shelters and government buildings as the ferocious storm took hold.

Seventeen people were killed in the state of Orissa and one person further south in the state of Andhra Pradesh, government and disaster management officials said.

"The 17 deaths were due to people being crushed by falling trees, walls, roofs," R.S. Gopalan, the senior state government official coordinating relief operations in Orissa, told AFP.

Some 600,000 people were left homeless in Orissa after the country's biggest cyclone in 14 years swept through 14,000 villages, the state's special relief commissioner, Pradipta Kumar Mohapatra, told AFP.

Families, who only hours earlier fled to shelters, returned to discover what was left of their flimsy homes. Many, holding their children, picked through the debris. Others simply sat on the ground in their village clutching bags of possessions.

"I lost my house and also a small shaving shop, I lost everything," Janardan, 32, who uses one name, said from inside his tiny dwelling in Gopalpur. The cyclone collapsed the roof, leaving Janardan and his wife to begin the clean-up.

The worst affected area, around the town of Gopalpur in Orissa where the eye of Phailin came ashore packing winds of 200 kilometres an hour (125 miles per hour), was still without power as emergency services rushed to help people living there.

Hundreds of workers from the country's National Disaster Response Force fanned out across the region, clearing away fallen trees from roads, mangled power poles and other debris, a statement said.

Other relief workers distributed food at shelters and treated the injured, while authorities worked to restore power and other services.

"Most of Orissa should have electricity back within 12 hours, by tomorrow morning. Water supplies should also be restored in much of the state later tonight," state official Gopalan said.

Some 1,000 people marooned by the storm surge in a village in Andhra Pradesh were rescued by boat, a top disaster response official told a press conference.

At the same press conference, vice chairman of the National Disaster Management Authority (NDMA) Marri Shashidhar Reddy put the total death toll slightly lower, at 14, with 13 killed in Orissa and one in Andhra Pradesh.

He praised relief workers for keeping the "death toll to a bare minimum".

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

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

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 on Saturday 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 Sunday 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."

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.

Despite the damage, there was a general sense of relief that things could have been a lot worse in Orissa and Andhra Pradesh.

"We were preparing for a super cyclone, but Phailin did not turn into a super cyclone," spokeswoman for the 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 873,000 people moved before the cyclone made landfall on Saturday evening, while at least another 100,000 were evacuated in Andhra Pradesh. Residents were also evacuated from coastal regions of West Bengal state.

The storm was moving north over Orissa with a speed of just 13 kilometres per hour, the India Meteorological Department (IMD) said.

Although the worst was over, the IMD 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.

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, IMD director general, told a press conference in New Delhi.

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.