A United Nations delegation will begin a three-day visit on Wednesday to a remote island in the Bay of Bengal where Bangladesh has relocated more than 13,000 Muslim Rohingya refugees since December despite criticism from human rights groups.

Bangladesh wants to finally relocate 100,000 of the more than 1 million refugees living in overcrowded border camps to the island of Bhasan Char, which emerged from the sea just two decades ago and is considered vulnerable to flooding.

The UN makes its first visit to the remote island of Bangladesh since the Rohingya moved

"This initial three-day visit will bring together experts from UN agencies involved in the response to Rohingya refugees in Bangladesh," the UN agency told Reuters in an email.

"The visit will analyze the current situation and facilities in Bhasan Char, assess the needs of the Rohingya refugees relocated there, and discuss with the authorities and others currently working in Bhasan Char."

The United Nations previously said that it had not been allowed to conduct a technical and security assessment of the island and that it was not involved in the transfer of refugees there.

Bangladesh says relocation is voluntary, but some of the first group to relocate spoke of being coerced.

The Rohingya, a minority group who fled violence in Myanmar, mostly Buddhist, are not allowed to leave the island, which is several hours' drive from the southern port.

Bangladesh has dismissed security concerns on the island, citing the construction of flood defenses as well as housing for 100,000 people, hospitals and cyclone centers.

It also says that overcrowding in refugee camps fuels crime, while some Rohingya said frequent violence in the camps had led them to relocate.

"We hope that any concerns the UN has about relocation will be removed and that they will engage in relocation and provide the Rohingya with the support they need," said a senior Foreign Ministry official.