The Flood Forecasting and Warning Centre predicts if there are more rains at the end of August, at least 25 districts will be affected by floods by September.
"We are taking all precautionary measures keeping the forecast in mind," Department of Disaster Management Director General Reaz Ahmed said.
He told bdnews24.com on Sunday "the forecasts we received from Met office, Flood Forecasting and Warning Centre and SPARRSO (Space Research and Remote Sensing Organisation), it is likely that the floods will spread to the mid-region of the country."
After a brief pause, 10 districts became submerged again in August due to incessant rains and water from the upstream.
At least seven people drowned in floodwaters in Dinajpur and six others died in Kurhigram. Some 400,000 people are stranded in Kurhigram. The vast areas of Gaibandha and Naogaon have been hit by floods now.
"If we are affected again, it may prolong," he cautioned.
The Water Development Board says the level of water rose at 77 of its 90 observation points.
Executive Engineer of the Flood Forecasting and Warning Centre, Sazzad Hossain, said water level in three rivers was on the rise threatening overflow and flooding to vast areas in the mid-region.
There are forecasts for more rains in August, and it will deteriorate the situation.
Considering the situation, deputy commissioners in 20 districts have been asked to keep flood shelters ready.
The districts include Dinajpur, Nilphamari, Lalmonirhat, Kurhigram, Thakurgaon, Panchagarh, Gaibandha, Bogra, Sirajganj, Sunamganj, Netrakona, Rangamati, Brahmanbarhia, Chandpur, Shariatpur, Madaripur, Faridpur, Rajbarhi and Gopalganj.
Disaster management department chief Reaz said it had allocated 1,075 tonnes of rice and Tk 4.5 million as relief for flood-affected people in seven districts. All the affected districts will get relief materials gradually, he added.
He believed the floods would not be as severe as those of 1988 or 1989.
However, BUET research fellow on water management Mohan Kumar Das said, "We have to wait for a few more days to understand the severity of the floods this year."
Bangladesh experienced the worst floods in decades in 1998 when 68 percent areas of it went underwater.
The floods in 1988 affected 61 percent areas. The flooding in 2007 was less severe than those of 1988 and 1998, affecting 40 percent of the country.
In 2013, it rained less than usual and only 10 percent areas were deluged. Around 30 percent areas were affected by the flooding in 2015.
To combat the situation this year, the government has cancelled regular holidays of all the officials as well as field workers involved with disaster management and relief activities.
They include workers of the Department of Disaster Management or DDM and Cyclone Preparedness Programme or CPP.