The death toll is likely to top 60 after a boat carrying Rohingya refugees overturned while attempting to flee violence in Myanmar, AFP reported.
"Twenty-three people have been confirmed dead ... 40 are missing and presumed drowned," International Organization for Migration spokesman Joel Millman told reporters in Geneva.
Surivivors from the accident have said that the boat was carrying about 80 people, including around 50 children.
The boat capsized after hitting a submerged object while passing along the city of Cox's Bazar, just meters from the coast, reported the BBC.
"They drowned before our eyes," said Mohammad Sohel to AFP. "Minutes later, the waves washed the bodies to the beach," he added.
Over 400,000 Rohingya Muslim refugees have fled to Bangladesh, according to the U.N. High Commissioner for Refugees, amid reported Myanmar government repression that began in August.
Rohingya people have suffered systematic persecution over many decades from the government, which considers them "illegal migrants" from Bangladesh.
Save the Children estimated that more than a million Rohingya refugees will seek safety in Bangladesh by January, saying that this figure includes at least 600,000 children who will be orphaned and consequently at risk of exploitation and trafficking.
The United Nations has referred to the waves of violence as an "ethnic cleansing" and called for massive international assistance to aid the ongoing Rohingya influx in Bangladesh.