A UN human rights expert blamed football's World Cup and the Olympic Games for forcing thousands out of their homes, as host cities sought "beautification" often at the expense of poor residents.
Raquel Rolnik, the United Nations Special Rapporteur on adequate housing, said the International Olympic Committee (IOC) had recently taken steps to try to protect housing during the bidding process for the 2016 Games.
In contrast, world football's governing body FIFA appeared to have done little to address housing concerns and had shunned UN queries since 2005, she added.
"I urge FIFA to open up, to be more transparent," Rolnik told journalists.
The UN expert acknowledged that the Olympics had brought redevelopment and created subsidised housing in some instances, notably in Athens and Moscow.
But sporting mega events often started off with evictions and local authorities rarely allowed the poor to return, Rolnik said in a report.
"Very rarely does the majority of the new housing stock go to those who need it the most," she told journalists.
The UN expert warned in a report that the economic benefits of staging such events are not spread evenly, as cities gave priority to "beautification over the needs of local residents".
She highlighted the removal of 20,000 people from the Joe Slovo settlement in Cape Town to make way for rental housing for this year's World Cup in South Africa, saying they were moved to "impoverished areas".
"All the commitments for affordable housing were left behind and were not prioritised," as 2010 World Cup stadium projects fell behind schedule, said Rolnik.
With the Vancouver Olympics, local authorities squeezed housing plans as they ran into financing problems, she added.
In Britain, 400 people were forced out of the Clays Lane estate, which was demolished to make way for the 2012 Olympic Park in east London.
The report noted that several thousand athlete lodgings in London are subsequently meant to be turned into affordable housing.
Rolnik also cited evictions in Barcelona prior to the 2002 Olympic Games, in Beijing before the 2008 Games, and of 35,000 families in New Delhi before this year's Commonwealth Games in October, as well as pressure on the homeless in Atlanta (1996), Seoul (1988) and Vancouver.