The triple-deck ferry, M.V. Coco, floats after it tipped in the Tetulia River. (Firoz Ahmed/Associated Press)Rescuers recovered three more bodies from a ferry that capsized as passengers disembarked at a terminal in southern Bangladesh, bringing the death toll to 40 with scores still missing, authorities said Sunday.

"We don't know how many people are still trapped inside the ferry. But anyone still there has no chance of survival," police official Mohammad Bayezid said.

The triple-deck ferry, MV Coco, was travelling late Friday from Dhaka to the coastal town of Bhola and was crowded with people heading home to celebrate the Eid al-Adha festival, he said.

It tipped and its rear portion sank in the Tetulia River as many passengers scrambled to disembark at a terminal near Bhola, about 100 kilometres south of Dhaka, witnesses said.

It was unclear how many people were on board when the ferry capsized. ETV, a private television station, said the vessel was carrying more than 1,500 people when it left Dhaka. It said many people had already disembarked when the accident occurred.

Police said they were waiting for a rescue vessel coming from the southern city of Barisal to pull the submerged ferry from the water, but it was unclear whether it would be able to reach the shore because of the shallow water near the bank.

In Bangladesh, ferry authorities usually don't keep passenger lists, making it difficult to know the number of passengers on board.

Hundreds of anxious relatives massed on the sandy river bank near the terminal and searched for missing loved ones.

Some complained that rescue work was slow as officials were on holiday for Saturday's Eid celebration.