Grieving survivors and rescuers picked through the rubble left in the wake of a super cyclone that battered Bangladesh as the death toll reached over 2,200 and a government official declared the disaster "a national calamity".

Mohammad Abdur Rob, chairman of the Bangladesh Red Crescent Society, said the overall death toll from the cyclone could reach 10,000. "Based on our experience in the past and reports from the scene I would guess the death toll may be as high as 10,000," he told Reuters.

Bangladesh officials also expected the death toll to rise as the search for hundreds of people missing after Thursday night's storm intensified.

Military ships and helicopters were trying to reach thousands of people believed stranded on islands in the Bay of Bengal and in coastal areas still cut off by the devastating storm.

The disaster ministry had recorded 2,217 deaths by Sunday evening (Bangladesh time), but local media put the figure at more than 3,000. A much improved disaster preparedness plan has been credited with saving scores of lives.

Local officials in affected areas say the death toll given by the ministry is far below the real numbers.

"Some 2,000 people have died in my area alone," said Anwar Panchayet, chairman of Southkhali, in the district of Bagerhat.

A huge effort was underway to get food, drinking water and shelter to tens of thousands affected by the storm, the worst to hit disaster-prone Bangladesh since 1991 when nearly 143,000
people died.

Cyclone Sidr smashed into the country's southern coastline late on Thursday night with 250 kph (155 mph) winds that whipped up a five metre tidal surge.

Most of the deaths came from the surge washing away homes and strong winds blowing down dwellings. Many others drowned or were lost at sea.