Walls are going up around the hillside slums of Rio de Janeiro, further dividing a city already separated between rich and poor.

Beneath the gaze of the statue of Christ the Redeemer, work is nearing completion on one of 19 walls to be built around the city’s sprawling favelas — the informal and often crime-ridden shantytowns that are home to more than a million people.

Critics say that the concrete barriers, up to 3m high, will seal the favelas as ghettos, segregating the inhabitants by sealing them off from the richer areas.

“We had the Berlin Wall, we have the walls of Palestine, now the walls of Rio,” José Saramago, the author and Nobel laureate, said.

Sérgio Cabral, the Governor of Rio, has plans to surround 13 favelas in the south almost completely in a project that he says is designed to stop their sprawl destroying the last of the city’s forested peaks. In a city riven by violence, mistrust and social inequality, few believe him.

“The Government does not have access to the favelas, so they are going to encircle them,” says Rossino de Castro Diniz, the president of the Association of Rio Favelas.

About a fifth of Rio’s six million inhabitants live in its 946 favelas, which have grown rapidly in the past decade. Many are controlled by drug traffickers, armed police can enter only in force and every week people die in pitched gun battles.

In the Rocinha favela, home to an estimated 160,000 residents and the largest slum in South America, rubbish is piled up, sewers overflow and there is a huge rat infestation.

“I am totally against the wall,” says Antonio Ferreira de Mello, known locally as Shaolin, who is the president of the residents’ association. “It’s an offence to human dignity.”

He says that the association, despite struggling to cope with the rapid expansion of the favela, has banned further building on new land so the Government’s ecological argument is redundant. Instead, expansion in Rocinha is vertical — one storey on top of another.

At the highest reaches of Rocinha, among the trees on a vertiginous slope, a wall is also under way. Far below is the city and above there is nothing but trees. It is a wild place.

“There are a lot of animals here,” says Waldir Domingo da Silva, who lives in one of the wooden shacks in one of the highest reaches. “Snakes. Scorpions. It’s a forest.”

The authorities say that the walls are designed to keep it that way. Icaro Moreno Junior, the president of Emop, the Rio state public works department, says that if nothing is done the green space will be gone in ten years. “We are protecting the forest,” he says. “We’re not dividing people . . . It’s crazy to compare it to the wall of Berlin or the wall of the Gaza Strip.”

In Dona Marta, on the slopes of Corcovado below the statue of Christ and once one of Rio’s most dangerous favelas, a new wall is almost finished. Its building has been carefully co-ordinated with other public works and the project has more widespread support.

Joel Miguel Rondon, 52, is one of the many residents working on it. “It’s a good idea,” he says. “Protect the environment.”

Since the police took control of Dona Marta in November and installed a base there, it has also become more secure and state money has been spent on a crèche, new housing and a network of secure concrete walkways instead of the usual treacherous paths. A free tram that opened in May last year climbs the favela’s steep gradient, lifting passengers to its dizzy heights.

“It got better with the wall,” says José Raimundo Brito do Santa, 26. He says that his sister’s house has increased in value from £2,500 to £4,600 since the tram arrived in May 2008.

Joseli Sebastião, 51, is hanging out washing. She welcomes the changes in the favela that have accompanied the wall. “I want peace,” she says. “I want to live.”

Even tourists are seen in Dona Marta, says Marlene dos Santos, 56, smiling as she sells cold drinks from her tiny house. “Everything that’s coming here really helps.”

For Rubem César Fernandes, the director of Viva Rio, an NGO that works to reduce violence in the favelas, the walls are an aggressive symbol of deeper divisions within the city.

“A wall satisfies public opinion,” he says. “Symbolically it is control. It is a bad solution to a real problem.”

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