A UAE official told Reuters the UAE continues to work with the United States and other international partners to resettle remaining evacuees in a timely manner as per the original agreement. The official did not comment on the accusation that the Afghans were being detained.
"We understand that there are frustrations and this has taken longer than intended to complete," the official said.
The UAE official said the country is committed to ensuring Afghan evacuees live in safety, security and dignity, and said evacuees have received high-quality housing, sanitation, health, counseling, education and food services.
Human Rights Watch said it had received no responses to requests for comment from the UAE ministries of interior and foreign affairs.
The US State Department office that handles the relocation of Afghans told the rights group in a letter that the US commitment to resettling eligible Afghans - including those in Emirates Humanitarian City - is an "enduring one", the report said.
Private evacuation groups and the Emirati military flew thousands of Afghans into the UAE during the chaotic US withdrawal from Afghanistan that ended 20 years of war. Several private groups continued chartered evacuation flights after the US departure.
The evacuees were housed in Emirates Humanitarian City and Tasameem Workers City - apartment complexes converted into refugee housing - and many eventually were cleared for resettlement in the United States, Canada and other countries.
Between 2,500 and 2,700 Afghans, however, did not qualify for resettlement elsewhere and as of January remained in what the HRW report called "arbitrary detention".
The UAE official said the Gulf country has hosted more than 17,000 evacuees evacuated after the Taliban takeover of Kabul in August 2021, and has resettled around 87 per cent of them.
"Emirati authorities have kept thousands of Afghan asylum seekers locked up for over 15 months in cramped, miserable conditions with no hope of progress on their cases," said Joey Shea, Human Rights Watch's UAE researcher.
Sixteen Afghans interviewed late last year by the rights group said they could not freely leave the site, with security guards or minders watching them closely on hospital visits and during the only shopping mall visit they have been permitted.
The report said Emirati authorities are not abiding by international law and UN guidelines for dealing with asylum seekers and migrants, making their detention "arbitrary".
The UAE is not a party to the UN Refugee Convention.
Human Rights Watch called on the UAE to immediately release the Afghans, allow them access to "fair and individualized" processing to determine their refugee status and protection requirements, and permit them to live where they want until their cases are resolved.
The organization urged the US State Department to use its leverage to win the release of the Afghans and expedite any applications for asylum or humanitarian parole.
The United States has resettled more than 88,000 Afghans evacuated during and after the US troop withdrawal. Thousands who worked for the US government, however, remain in Afghanistan awaiting the processing of their special immigration visa applications.