Thousands of migrant workers building a major island development in Abu Dhabi are facing exploitation and abuse, the New York-based Human Rights Watch says.
It says workers on Saadiyat island - which is to include a Guggenheim museum and a branch of the Louvre - reported conditions amounting to forced labour.
HRW called on global cultural bodies involved to obtain guarantees that workers' rights would be respected.
The Abu Dhabi-owned company behind the project says the report is misleading.
HRW's report cites "unlawful recruiting fees, broken promises of wages, and a sponsorship system that gives an employer virtually complete power over his workers".
It adds: "While the UAE government has moved to improve housing conditions and ensure the timely payment of wages in recent years, many labour abuses remain commonplace."
The island is planned to be the centre of a showcase "cultural district" in Abu Dhabi, the capital of the United Arab Emirates (UAE).
But Abu Dhabi's Tourism Development and Investment Company (TDIC) - the government body overseeing development work - rejected the claims of worker abuse, saying construction on the project had not even begun.
Bassem Terkawi, a spokesman for TDIC, said workers on Saadiyat are currently building housing for the 20,000 or so labourers who will start work on the project within the next 12 months.
On a government-organised tour for journalists, he told AFP news agency that the existing workers were also being housed in "quality" accommodation.
In a statement, TDIC said special care was been taken to ensure workers' welfare, with contractors being obliged not to seize passports and to pay workers on time.
The UAE has taken steps to improve conditions for foreign labourers, who are mostly from South Asian countries, after repeatedly coming under fire by rights groups over the past few years.
The country's labour ministry announced plans on Tuesday to set up special labour courts, encourage "model" housing, and allow workers to change jobs if employers fail to pay wages for more than two months, Reuters news agency reported.