(CNN) He's the migrant worker busting a gut to build Qatar's shiny soccer stadiums that will host FIFA's World Cup in 2022 -- at a price.

For Prem -- a metal worker and father of three from Nepal who carried out work on the Khalifa International Stadium in Doha between February and May 2015 -- that price was the loss of his family's home after he experienced a three-month delay in being paid, according to Amnesty international.

Prem is just one example of ongoing exploitation of migrant workers in Qatar at a venue for the 2022 World Cup that soccer's world governing body FIFA can no longer turn "a blind eye" to, says the human rights organization's new report published Thursday.

Amnesty said it has found evidence of "systematic abuses," including forced labor of migrant workers at the Khalifa Stadium.

"If the system in Qatar doesn't change, then every man, woman and child who goes to the World Cup is likely to meet a migrant worker who is exploited," Audrey Gaughran, Amnesty's director of global issues and research, told CNN in a phone interview.

'Ugly side of the beautiful game'

Amnesty's 80-page report, titled "The ugly side of the beautiful game: Labor exploitation on a Qatar World Cup venue," is based on interviews in the year to February 2016 with 234 male migrants working either in construction at the Khalifa Stadium or in landscaping at the Aspire Zone Complex, where top European soccer clubs such as Bayern Munich, Manchester United and Paris Saint-Germain have trained.

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The abuses found include: workers living in "squalid and cramped accommodation"; employers confiscating workers passports; workers being threatened for complaining about working conditions; workers having to pay as much as $4,300 to recruiters in their home country to get a job in Qatar, along with some not being paid for months.

However Qatar said the "tone of Amnesty International's latest assertions paint a misleading picture."

"We have always maintained this World Cup will act as a catalyst for change -- it will not be built on the back of exploited workers," said the gulf kingdom's Supreme Committee for Delivery & Legacy in a statement sent to CNN. "We wholly reject any notion that Qatar is unfit to host the World Cup.

"Amnesty International's investigation was limited to just four companies out of more than 40 currently engaged on Khalifa International Stadium. The conditions reported were not representative of the entire work force on Khalifa.

"Many of the issues raised had been addressed by June of 2015, months before the publication of Amnesty's report."

'Living nightmare'

The FIFA World Cup is the world's most-watched sports event, generating more than $5 billion from broadcast and marketing contracts.

"The abuse of migrant workers is a stain on the conscience of world football," Amnesty International General Secretary Salil Shetty said in the organization's press release.

"For players and fans, a World Cup stadium is a place of dreams. For some of the workers who spoke to us, it can feel like a living nightmare," Shetty said.

FIFA and its sponsors should push for change, or risk being "tainted by association," Amnesty warned.

Qatar's migrant workers, mostly from South Asia, make up more than 90% of the country's workforce. Building for the 2022 World Cup is expected to peak in 2017, when the current workforce of 4,000 migrants on World Cup sites will jump to 36,000, according to FIFA.

This is Amnesty's fifth investigative, in-depth report on migrant workers conditions at World Cup venues in Qatar, and the first since Gianni Infantino was elected FIFA president in February. He has vowed to restore the ruling body's battered reputation after years of corruption scandals under his predecessor, Sepp Blatter.

"We remain convinced that the unique attraction and visibility of the FIFA World Cup globally is a strong catalyst for significant change," FIFA said in a statement sent to CNN in response to Amnesty's latest report.

"This is an ongoing process. Challenges remain, but FIFA is confident that the structures and processes set up so far by the Supreme Committee for Delivery and Legacy, which is the entity responsible for the delivery of FIFA World Cup infrastructure, provide a good basis to monitor labor rights of migrant workers on FIFA World Cup stadium construction sites."

In a letter sent to Amnesty dated March 17, FIFA said "we do not agree" with the group's conclusion it had taken no action to tackle human rights abuses of workers at World Cup sites.

Without addressing any of the individual cases of abuse highlighted by Amnesty, FIFA pointed to a number of initiatives, including making labor rights part of its bid process for future events, meetings with "the highest authorities in Qatar" since 2011 about human rights issues, inspection visits of building sites and workers housing and its hiring of a so-called "Human Rights Manager" at its Zurich headquarters.

'Serious job do to in Qatar'

Amnesty said Qatar has yet to deliver any real labor reforms since becoming the first Middle East nation to win the right to host the World Cup.

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Although Amnesty said Qatar's Supreme Committee for Delivery and Legacy, which is responsible for delivering the 2022 World Cup, had shown "consistent commitment" to improving workers' rights, it wasn't doing enough to monitor and enforce its own welfare standards established in 2014.

It said it was down to FIFA to enforce real change.

"FIFA need to recognize they have a serious job do to in Qatar," Gaughran told CNN. "There needs to be much more effective enforcement of the worker welfare standards that exist for World Cup sites, because our research has shown that they're not being implemented effectively at all."

FIFA should also ask Qatar to reform its notorious sponsorship system, under which migrant workers cannot change jobs or leave the country without permission of their employers.

"There is a very serious problem with the sponsorship system that keeps workers very much tied to their employers," Gaughran added. "FIFA needs to engage with Qatar on that and it is probably quite reluctant to do so."

The human rights agency called on World Cup sponsors including Coca-Cola, Adidas and McDonald's to put FIFA under pressure to improve the situation.

Last year, Coca-Cola and Visa issued statements saying they expected FIFA to address such claims of human rights abuses.

'I can't sleep at night'

Metal worker Prem's problems started in September 2014.

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"At the start of 2014 there was no problem, I was getting my monthly pay and sending back money to my wife to cover my (recruitment) loan and the rent for our house (in Nepal)," he told Amnesty. "We also look after my parents."

But because he wasn't getting paid, Prem's family could no longer keep up with loan and rental repayments and ended up losing their home.

"My family is now homeless and two of my younger children have been taken out of school," he said. "My parents had to shift to my brother's house in our village, but it is far and there are no facilities there.

"Every day I am in tension, I cannot sleep at night. This is a torture for me."

Photos: 2022 World Cup: A $200B work in progress Photos: 2022 World Cup: A $200B work in progress Qatar's grand plan – The Khalifa International Stadium "will fit 40,000 spectators and be completely cooled, including the field of play, all seats and concourses," soccer's world governing body FIFA said in September 2015. But what's the human cost of this World Cup venue's construction? Hide Caption 1 of 16 Photos: 2022 World Cup: A $200B work in progress Amnesty accusation – In a new report published on Thursday, human rights organization Amnesty International said it had found evidence of "systematic abuses," including forced labor of migrant workers at the Khalifa International Stadium in Doha. Hide Caption 2 of 16 Photos: 2022 World Cup: A $200B work in progress Qatar's World Cup win – In December 2010, then FIFA president Sepp Blatter revealed Qatar as host of the 2022 World Cup at a ceremony in Zurich, Switzerland. But both Qatar and FIFA soon faced allegations about poor working conditions and abuse of immigrant workers brought in to build the facilities for the tournament. Hide Caption 3 of 16 Photos: 2022 World Cup: A $200B work in progress Glittering prize – Men at a shoemaker's stall sit by a replica of the World Cup trophy soon after the hosting award brought announcements of a wide variety of infrastructure projects, including the construction of new stadiums and roads. Hide Caption 4 of 16 Photos: 2022 World Cup: A $200B work in progress 'A stain on the conscience of football' – "For players and fans, a World Cup stadium is a place of dreams," Amnesty International general secretary Salil Shetty said. "For some of the workers who spoke to us, it can feel like a living nightmare." Hide Caption 5 of 16 Photos: 2022 World Cup: A $200B work in progress Evidence of 'abuses' – FIFA and its sponsors should push for change, or risk being "tainted by association," Amnesty warned. But in a statement, Qatar's Supreme Committee for Delivery and Legacy said it was "committed to ensuring the health, safety and wellbeing of every worker on World Cup projects." Hide Caption 6 of 16 Photos: 2022 World Cup: A $200B work in progress Big-money developments – An artist's impression shows what the finished Khalifa stadium will look like. Qatar is spending a reported $200 billion -- more than any previous World Cup host -- on nine new air-conditioned stadiums, the major refurbishment of three venues and infrastructure. Hide Caption 7 of 16 Photos: 2022 World Cup: A $200B work in progress Examining conditions – A worker bedroom in the Al Wakrah camp, pictured in May 2015. Amnesty's fifth investigative, in-depth Qatar World Cup report is its first since Gianni Infantino was elected as FIFA president in February 2016. Hide Caption 8 of 16 Photos: 2022 World Cup: A $200B work in progress 'Squalid, cramped accommodation' – Conditions at the Al Wakrah camp were described as "cramped, dirty and unhygienic." The new Amnesty report describes how many workers are living in "squalid accommodation," but Qatari officials say they are steadily improving the situation from where it stood in 2015 and denied the 2022 World Cup would be "built on the back of exploited workers." Hide Caption 9 of 16 Photos: 2022 World Cup: A $200B work in progress 'Five years of promises' – Here, a reporter takes a picture of a squalid kitchen at a camp housing foreign workers in Doha in May 2015. The Qatari government has announced new projects to provide better accommodation. Hide Caption 10 of 16 Photos: 2022 World Cup: A $200B work in progress Returning to base – Foreign laborers working on the construction site of the al-Wakrah football stadium, one of Qatar's World Cup venues, walk back to their accommodation compound after a working day in May 2015. Hide Caption 11 of 16 Photos: 2022 World Cup: A $200B work in progress 'No reforms' – Amnesty said Gulf desert emirate Qatar had yet to deliver any real labor reforms since becoming the first Middle East nation to win the right to host the World Cup. Hide Caption 12 of 16 Photos: 2022 World Cup: A $200B work in progress 'Struggling to enforce standards' – Shetty said Qatar's World Cup delivery committee is struggling to enforce the standards it has set companies working on its venues. Hide Caption 13 of 16 Photos: 2022 World Cup: A $200B work in progress Call for FIFA diligence – Amnesty has urged FIFA to start a "human rights due diligence process" by carrying out its own inspections of labor conditions in Qatar and makings its finding public. Hide Caption 14 of 16 Photos: 2022 World Cup: A $200B work in progress Sending a message – Demonstrators hold placards calling for change to Qatar's policies on the working conditions of migrant workers ahead of the international friendly between Scotland and Qatar in Edinburgh in June 5, 2015. Hide Caption 15 of 16 Photos: 2022 World Cup: A $200B work in progress Pressure from sponsors – An artist's impression for Qatar's flagship Doha Port stadium prior to the World Cup bid in 2010. Hide Caption 16 of 16