A UN official called on Qatar on Sunday to abolish a sponsorship system for migrant workers he said was a source of labour abuse, raising pressure on the 2022 World Cup host for reforms of its workplace practices.
Francois Crepeau, UN Special Rapporteur on the human rights of migrants told a news conference in Doha that living conditions of foreign workers tended to be poor, describing one compound he had visited as a "slum".
"This marks a stain on Qatar's reputation and is something that can be improved right away," he said.
Faced with the challenge of completing big construction and infrastructure projects before the World Cup, the Gulf state has an increasing number of its estimated 1.8 million foreigners working on projects related to football's showcase event.
Crepeau said the sponsorship, or kafala, system, a practice widely used in the Gulf, ought to be scrapped.
"This system that is used to regulate the relationship between employers and migrant workers, with a work permit linked to a single employer, is problematic and a source of abuse against migrants," he said.
Under the system, employees cannot change jobs or leave the country without the permission of their sponsors, who are often labour supply companies or wealthy individual Qataris who provide workers to businesses for personal profit.
Many sponsors confiscate the passports of guest workers for the duration of their contract. Most foreign workers are in the construction and domestic work sectors.
Crepeau said that despite some improvements to labour regulations, implementation was still lacking.
Qatari Labour Ministry officials were not immediately available to comment.
Britain's Guardian newspaper reported in September that dozens of Nepali workers had died during the summer in Qatar and that laborers were not given enough food and water. Officials from Nepal and Qatar denied the report.
However, Nepal recalled its ambassador from Qatar on Thursday after it emerged that she had called the country an "open jail" for Nepalis who suffer labor abuses.
Crepeau also visited detention centers where women were serving one-year terms for adultery - an offence under Islamic law - after giving birth out of wedlock. He said the women lived in prison with their babies in conditions he said were a clear violation of the U.N. Convention on the Rights of the Child.
Thousands of mostly African workers gathered in the Saudi capital Riyadh on Sunday seeking repatriation after two people died in overnight rioting that followed a visa crackdown in the kingdom, which also uses the sponsorship system.