Around 100 protesters from Building and Wood Workers International (BWI) and the Swiss union Unia gathered at the front gates waving red cards as FIFA's executive committee began a two-day meeting to discuss the tournament.
FIFA will debate whether, in principle, they should move the event from the June-July period, in the searing Qatari summer, as well as the situation of migrant workers who will be working on World Cup construction sites.
Britain's Guardian newspaper reported last week that dozens of Nepali workers had died on building sites in Qatar over the summer.
Meanwhile, the International Trade Union Confederation (ITUC) said current mortality figures for workers from Nepal and India, who account for the bulk of the 1.2 million migrant workers in the country, show on average 400 workers die each year.
"Those people working on the sites have nothing, they suffer," BWI assistant general secretary Marion Hellmann told reporters. "There is still a lot of time to change. We want to have an abolition of the sponsorship system, for example, where people are bound to their employer, their passport is withheld and they cannot escape.
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"We want to get labour inspectors in place to go to the sites and do inspection work. We want to get a very clear commitment from the (Qatar) government and from FIFA," he added.
"We want people to have drinking water, food, a good bed to sleep, good air-conditioned rooms, good salary, not just seven dollars a day.
"We still have 10 years to go, good time to make changes."
Swiss-based BWI says it groups together around 328 trade unions representing around 12 million members in 130 countries.
FIFA have already expressed concern over reports of working conditions and the world players' union FIFPro has said it is "deeply alarmed."
