A company owned by Qatar's royal family has been accused of enforcing some of the "worst conditions" for migrant workers constructing FIFA World Cup stadiums and hiding mistreatment from the football authority's inspectors...

Fresh revelations have now emerged about Hamad Bin Khalid Contracting Company (HBK), which is owned by Qatar's ruling family the House of Thani and was awarded several contracts to build World Cup stadiums. 

"Our report found that one of the largest companies involved in the construction of these stadiums is the HBK company and that is owned by the Qatar royal family," Equidem's Namrata Raju said.

"Some of the worst conditions that we found were actually in stadiums that were being constructed by this company...

The Equidem report has found that while these inspections occurred during the construction of some stadiums, HBK moved workers to different locations when those check-ups were planned...

HBK did not respond to the ABC's request for comment.