Officials say none of them are being moved against their will, and that it would ease overcrowding in camps that are home to more than 1 million Rohingya who have fled neighbouring Myanmar.
Authorities in Bangladesh on Friday started sending a first group of more than 1,500 Rohingya refugees to an isolated island despite calls by human rights groups for a halt to the process.
The south Asian nation says it is only moving refugees who are willing to go and that this will ease chronic overcrowding in camps that are home to more than 1 million Rohingya, members of a Muslim minority who have fled neighbouring Myanmar.
"The government is not taking anyone to Bhashan Char forcibly. We maintain this position," Foreign Minister Abdul Momen told reporters late on Thursday.
Naval officials said seven boats would be used to transport the Rohingya, with two more carrying supplies.
More than 300 refugees were brought to the island earlier this year after several months at sea in an attempt to flee Bangladesh.
Was the relocation forced?
Refugees and humanitarian workers say some of the Rohingya had been coerced into going to Bhashan Char, a flood-prone island that emerged from the sea 20 years ago.
Refugees International said the move was "nothing short of a dangerous mass detention of the Rohingya people in violation of international human rights obligations".
Aid workers said refugees had come under pressure from government officials who used threats and offers of cash and other enticements to persuade them to go to the island.
The United Nations said it had "limited information" about the relocations and was not involved in preparations.
Reuters quoted two refugees as saying their names appeared on lists compiled by government-appointed local leaders without their consent.
"They have taken us here forcefully," a 31-year-old man told Reuters tearfully by phone as he boarded a bus from the camps near Cox's Bazar.
"Three days ago, when I heard that my family is on the list, I ran away from the block, but yesterday I was caught and taken here," he said.
An 18-year-old woman said her husband had put their names on the list thinking it was for food rations. He fled when they were told to go to Bhasan Char, she said, adding that she is also hiding in the camp.
Why are the Rohingya displaced?
Three years ago, a military operation in Myanmar destroyed entire Rohingya Muslim villages.
UN investigators say as many as 10,000 people were killed and more than 730,000 Rohingya fled the massacre for Bangladesh, calling it "textbook ethnic cleansing."
Myanmar denies genocide and says its forces were targeting Rohingya militants who attacked police posts.
