The Bangladesh army says it has reached most parts of the country's southern coast, six days after a cyclone struck.
But correspondents say much more needs to be done to bring food, clean drinking water, medicine and shelter to those who survived Cyclone Sidr.
There is anger among many villagers. Millions are still at risk from food shortages and water-related diseases.
The storm has affected about one million families and at least 3,100 people are confirmed dead so far.
The death toll is expected to rise.
Relief officials say a huge operation by civil authorities and the army, navy and air force is now in full swing.
A number of roads blocked by trees have been cleared and communication links have been restored. BBC reporters have seen helicopters criss-crossing the skies.
Army major Emdadul Islam told the AFP news agency: "We have reached everywhere with relief materials and we are also continuing rescue operations."
UN relief co-ordinator Renata Lok Dessallien led a team of donors to visit badly-hit areas on Wednesday.
"There are some inaccessible places, where people were yet to get relief. But officials working in the field have assured that they will reach those places soon," she told Reuters news agency.
The BBC's Alastair Lawson, who is in the storm-hit area, says many people are badly in need of food. Aid is getting through, he says, but not in large enough quantities.
Some people have barely eaten since the storm struck and our correspondent has witnessed villagers fighting over rice.
The other big concern is how to get clean water and prevent the spread of disease, he says.
The Associated Press news agency reported that more than 2,000 people turned up for food aid in one village, Purba Saralia, when there were supplies for only half that number.
"This is a crisis. I don't have enough food and we have no work," one farmer, Lal Mia, told the agency.
"We have nothing left," said another man in the village of Balkultola.
Cyclone Sidr, which struck late on Thursday, packed winds of up to 240km/h (150mph) and a tidal surge of several metres.
It brought down power lines and wiped out vital crops.
Bangladesh's Red Crescent society says up to 10,000 may have died.
On Tuesday Bangladesh called for more aid for tens of thousands of cyclone survivors. The government has urged aid agencies to co-ordinate with local authorities.
Coastal Bangladesh is a maze of waterways, creeks, islands and sandbanks and the only way to reach the area is by boat. The government's early-warning system is being credited with saving many lives.
Officials say that in many areas 95% of rice has been destroyed, while shrimp farms and other crops were simply washed away.
Southern Bangladesh is hit every year by cyclones and floods, but Cyclone Sidr is the most destructive storm to hit the country in more than a decade.
Another storm in 1991 left some 143,000 dead.