At least 51 people have died and more than a million affected by heavy rainfall in Bangladesh in recent days.

Thousands have lost their homes as flash floods and landslides hit large parts of the country, including the capital Dhaka.

More than half the deaths so far have occurred in Cox's Bazar, home to a large Rohingya refugee population. Last week several students and a teacher were killed in that district when floodwaters swept through their school.

Bangladesh is a low-lying country that has many rivers, and often sees heavy rain and floods during its annual monsoon season. But experts warn that climate change has made rainfall more intense and more frequent.

The heavy rain began more than a week ago and as it intensified in recent days, authorities issued warnings about floods and landslides, evacuated families in high risk areas, and postponed student exams.

Thousands of people are now living in government shelters.

As of Sunday, more than 1 million people have been affected by the rain, according to authorities.

Twenty-eight out of the 51 deaths reported so far have been in Cox's Bazar. The district is home to more than a million Rohingya who make up the world's largest refugee settlement.

In Dhaka, traffic has slowed in the capital as residents report of flooded streets, with the water rising up to knee level in some areas, according to BBC Bangla.

Some local media outlets on Monday questioned previous government efforts to fix the drainage systems in Dhaka.

Sarder Udoy Raihan of the Flood Forecasting and Warning Centre told the AFP news agency that the situation in the southeast of the country was likely to improve soon.

But with the monsoon continuing to affect the northeastern and northern parts of Bangladesh, "there is a possibility of further inundation", he warned.