The charity has produced a 52-page report, which includes anecdotal evidence about how one worker was forced to find food to eat from waste bins, and another who worked for five months without a day off - and without pay.
Hundreds of migrant workers in Qatar have gone without pay and many were forced to return to their home countries without compensation, despite recent reforms meant to improve worker rights, a report from Amnesty International said on Thursday.
The Amnesty investigation into three Qatari companies involved in construction and cleaning - Hamton International, Hamad bin Khaled bin Hamad and United Cleaning - found that at least 1,620 workers had submitted complaints after their wages were stopped for several months before their contracts were ended.
A new report from the human rights group says thousands of workers are going unpaid.
After coming under fire over the treatment of migrant workers, Qatar in 2017 agreed with the International Labour Organization to undertake labor reforms, including establishing new dispute resolution committees. In response to the ongoing problems, past year it was announced that Qatar would introduce a Workers' Support and Insurance Fund.
Amnesty says nearly a year later, the Fund remains unfunded and unused.
"No matter the critical guarantees of reform which Qatar has made earlier than the 2022 World Cup, it remains a playground for unscrupulous employers", concludes Stephen Cockburn, Amnesty's deputy director of worldwide disorders.
Meanwhile, a spokesman at the Government Communications Office of the State of Qatar insisted the country would deal with any problems raised in the report.
"In line with Amnesty International, we however acknowledge the importance of the new Labour Dispute Committee as an important part of the broader labour rights reforms taking place in Qatar". They said: "We would like to note that, as confirmed by Amnesty International, the report does not concern World Cup sites". We continue to work with NGOs, including the International Labour Organisation, to ensure that these reforms are far-reaching and effective.
Amnesty World has launched a blistering assault on Qatar for failing on its guarantees to tackle stylish migrant employee exploitation earlier than the 2022 World Cup. "We have said, from the outset, that this would take time, resources and commitment", it said. Any issues or delays with our systems will be addressed comprehensively.
Qatar's climate has also been partly blamed by experts for high mortality rates among migrant construction workers.
According to Amnesty, the workers, who did not work on World Cup projects, took their complaints to dispute panels set up by the Qatari government which were completely ineffective.
In response to the report, Federation Internationale de Football Association was quoted as saying that World Cup sites were not specifically mentioned and that the contractors cited "have never been engaged on World Cup projects in Qatar".
"Fifa continues to engage with the Supreme Committee for Delivery and Legacy and other parties towards ensuring respect for the rights of workers who are involved in Fifa World Cup-related activities".