The World Cup and the Olympics are being used as a pretext for "social cleansing" as tens of thousands of Rio slum dwellers are driven out to the city periphery, favela residents say.

While millions of eyes turn to north-eastern Brazil for the World Cup draw on Friday, poor communities in Rio de Janeiro are still struggling to be heard as they fight against evictions they say are related to the city's mega sporting events.

Next year, Rio will host seven games, including the final, followed in 2016 by the Olympics. The city's mayor, Eduardo Paes, describes this as an opportunity for the city to modernise and create a legacy for future generations. But many of those on the frontline of change feel they are the victims of social cleansing.

At least 19,000 families have been moved to make way for roads, renovated stadiums, an athletes' village, an ambitious redevelopment of the port area and other projects that have been launched or accelerated to prepare the city for the world's two biggest sporting events.

"The authorities wouldn't even enter our community in the past and there was no mention of moving us, but then Brazil won the right to host the World Cup and everything changed," Maria do Socorro told a hearing in the city council building this week. Socorro's home of 40 years in the Indiana favela has been marked for demolition.

Countless communities are affected. Among the best known are Vila Autódromo, which will be the site of the main Olympic stadium and athletes' village; Providência, which is close to the port redevelopment and Indiana, which is about 10 minutes' drive from the newly refurbished Maracanã stadium.

As was the case in Beijing, London and South Africa before their mega events, the government says such programmes are necessary to modernise the city. Numerous relocations have been carried out in the past as Rio has evolved, but politicians and campaigners say the forthcoming sporting events are driving the process forward at an unprecedented rate, and often in violation of the law. "The government is obliged to publicise preliminary studies, listen to the views of affected communities and offer alternative housing close to their old homes, but the Rio municipality has not complied with any of these laws," said Renata Silva, a council member for the leftwing PSOL party.

"People are being moved more than 40km [25 miles] from their homes with very little prior notice and no compensation."

Civil society groups say the relocations are motivated by surging land values. As new infrastructure is put in place for the World Cup and Olympics, property prices rise in the surrounding areas.

"There is a process of gentrification taking place in the whole city that is connected to the sports events and how the government sees the city: it is no longer a place for residents, but as a business to sell to foreign investors. That's what the World Cup is about," said Renata Neder of Amnesty.

"There have been waves of evictions in the past, but this latest one that began after Rio was chosen to host the mega events may be the biggest one yet in terms of numbers."

The authorities insist that due process has been followed and no residents have been forcibly relocated. The Rio 2016 chief operating officer, Leo Gryner, said the high-profile case of Vila Autódromo showed how far the government was willing to go to accommodate residents.

"In Vila Autódromo the mayor said he would move people to a new place and build nice housing projects for people to move to a new area. People started protesting, saying you couldn't evict people because of the Olympics. So after some time, the city admitted they should not have forced them to go. They talked to each one of the people living in that area, roughly half said they wanted to move and the other half wanted to stay," he said.

"Then when they started to see the project going up they realised it was very nice and so they came here to demonstrate and demand to be moved to the new housing! The city talked to everyone." This is refuted by residents.

That is disputed by residents. And in less prominent cases, residents complain of being harassed by officials and engineers who tell them their homes are not safe. In some cases, this is true. Thousands have died over the years in the floods and landslides that affect many river and hillside favelas during the annual rainy season.

But a visit to the Indiana favela, which sits next to the river Maracanã, suggested the genuine threat to a handful of homes may be being used to justify the clearance of swaths of the community.

Several houses, including two wooden shacks, sat below the flood line and looked too poorly built to withstand a deluge. But the majority of homes marked for demolition – including several that had already been destroyed – were on seemingly firm concrete foundations several metres above the flood line.

"It is true that there are risks from the river, but only in certain places. The problem is that the government is arbitrarily trying to move everyone, even those who are not at risk," said Ines Ferreira de Abril, a local health worker.

"Many people have already moved out under the relentless pressure from the government. They are going house by house and ultimately, they want to get rid of all of us because this land is very valuable now. They want us out of the way before the big events."