The United Arab Emirates (UAE) is failing to protect migrant workers from serious abuse by employers, pressure group Human Rights Watch has said.
The UAE is undergoing a building boom on the back of oil profits
Hundreds of thousands of mainly foreign labourers are employed in construction booms in Dubai and elsewhere.
But according to Human Rights Watch (HRW), they are often poorly paid and made to work in dangerous conditions.
Labour reforms unveiled last week by the government were welcome but more must be done to enforce them, HRW said.
Among the measures ordered by the UAE's prime minister were a crackdown on health and safety standards and a new health insurance scheme for workers.
Sheikh Mohammed bin Rashid al-Maktoum was widely praised for his foresight when he announced the reforms, says the BBC's Julia Wheeler in Dubai.
But, she says, his timing has now prompted suggestions the government - given a copy of the report last month - wanted to pre-empt criticism of its track record.
'Death and injury'
Migrant workers, who generally come from India, Pakistan and China, have been badly treated in the UAE for decades.
Based on interviews with 60 labourers, the HRW report - called Building Towers, Cheating Workers - highlights the "serious abuse" involved.
Labourers are often paid extremely low wages and have to work for several years to pay off debts to unscrupulous labour recruiters, the report says. Bosses also widely withhold workers' passports.
On top of this, labourers toil in "hazardous working conditions that result in apparently high rates of death and injury".
The prime minister's new measures are "a welcome step in the right direction", said HRW Middle East director Sarah Leah Whitson.
"But unless the government starts to hold employers accountable for breaking the law, the UAE's colossal new skyscrapers will be known for monumental labour violations."
HRW also points out that a government promise to draft laws by the end of the year allowing labourers to form trade unions has not yet been fulfilled.
Instead, a new law passed in September banned strike action.