Thousands are left stranded, without power and electricity, as floods and landslides ravage roads and vital infrastructure while 66,000 homes have been destroyed, according to IFRC.
Food and clean water shortages are being reported, as well as a rise in waterborne diseases.
"These communities are reeling under the full force of the monsoon rains and the ensuing floods and landslides. Even if the rains recede, overflowing rivers upstream will worsen the flooding in the coming days,” said Azmat Ulla, head of IFRC's Bangladesh office.
There are fears that destruction of crops may lead to food shortages with children, breastfeeding mothers, pregnant women, and the elderly being identified as most vulnerable.
The Bangladesh Red Crescent Society accordingly mobilised 675 volunteers to support communities in the flood-affected districts.
In addition to carrying out rapid assessments, teams are distributing food, clean water, hygiene kits and tarpaulins to families whose homes were destroyed or damaged by the landslides.
“Tens of thousands of homes have been destroyed which puts people further in the direct path of dangerous floods. We are seriously concerned about access to the affected populations," Md Feroz Salah Uddin, secretary general of the Bangladesh Red Crescent Society, said.
A critical priority for Bangladesh Red Crescent volunteers right now is to reach these stricken communities with relief supplies.”
IFRC has also disbursed 452,439 Swiss francs from its Disaster Relief Emergency Fund that will allow the Bangladesh Red Crescent Society to provide food, relief items and cash for 10,000 of the most affected families living in the worst hit districts.