FIFPro, which represents around 50,000 professional footballers worldwide through its national affiliates, said that independent experts must be allowed to inspect worksites and ensure international labour standards are adhered to.
"Qatar must respect the rights of the key people who will deliver the 2022 World Cup: the workers who build the World Cup stadia and infrastructure and the professional footballers who play in them," FIFPro said in a statement on Friday.
"FIFPro...calls on the international football community to act with solidarity to ensure that the 2022 World Cup in Qatar is only delivered in accordance with football's universal values as set out in the statutes of (soccer's governing body) FIFA."
It added: "FIFPro is deeply alarmed by reports of the brutal exploitation of migrant workers by construction companies in Qatar who are involved in building the stadia that FIFPro members will be expected to play in."
The Guardian report, published on Wednesday, said thousands of Nepalese workers were enduring labour abuses as Qatar prepares to host the 2022 World Cup.
The Qatar 2022 Supreme Committee said in a statement it had been informed that government authorities were investigating the allegations.
"The 2022 World Cup was awarded to Qatar to promote football and, more importantly, football's universal values in the Middle East," said Brendan Schwab, head of FIFPro's Asian division.
"This can only be achieved if Qatar respects the rights of the key people who will deliver that World Cup: the workers who build the World Cup stadia and the players who play in them."
"If these reports are true, then football must act," Schwab added. "It is inexcusable for workers' lives to be sacrificed, especially given modern health and safety practices in the construction industry.
"FIFPro assumes that adherence to FIFA's principles and international labour standards are conditions on which Qatar was awarded the extraordinary privilege of hosting football's greatest event.
"FIFA has previously acted to ensure international labour standards are respected when it worked with the International Labour Organisation (ILO) in the fight against child labour in the manufacture of footballs. A similar initiative is urgently needed in Qatar.
"Further, independent workplace health and safety experts appointed by FIFA and the ILO must be permitted to inspect all worksites and make binding recommendations to ensure international labour standards are respected in Qatar."
FIFA's executive committee will discuss the Qatar situation when it meets in Zurich next week.
The committee is also expected to approve in principle that the tournament be staged away from the summer months of June and July.