World Cup sponsors Visa and Coca-Cola have expressed concerns over conditions facing migrant workers constructing projects for the 2022 tournament in Qatar.
Visa said it had "grave concerns", and said it was "troubled by the reports coming out of Qatar related to the World Cup and migrant worker conditions".
"We have expressed our grave concern to Fifa and urge them to take all necessary actions to work with the appropriate authorities and organisations to remedy the situation," it added.
Coca-Cola, another sponsor, also issued a statement today saying it has worries about migrant workers' treatment.
"The Coca-Cola Company does not condone human rights abuses anywhere in the world," it said.
"We know Fifa is working with Qatari authorities to address specific labour and human-rights issues. We expect Fifa to continue taking these matters seriously."
The move comes two days after the launch of a campaign to challenge human rights abuses at World Cup construction sites in Qatar.
Sharan Burrow, the general secretary of the International Trade Union Confederation (ITUC), called the country a "slave state".
The discrimination, the racism, the denial of rights for 1.4m migrant workers adds up to apartheid and a model of employment that is simply slavery. There is a conspiracy of silence by governments and major sporting and cultural institutions that allow it to continue.
Earlier this week BBC journalist Mark Lobel and his TV crew were arrested while reporting on conditions for labourers in Doha.
Lobel was questioned, before being taken to a local prison and held overnight.
"[The crew] trespassed on private property, which is against the law in Qatar just as it is in most countries," a statement from the Qatari government said.