The police hardly seem to notice the men as they drive down the street of the area that is known as "Little Plumstead", after a town in Zimbabwe.

A Zimbabwean woman, who is standing nearby laughs when asked if the police ever harass her. "Sometimes they come for us, but mostly they go for the ones in the suburbs after they have finished work because they know that they have money then."

"Money for what?" she is asked. "Money for bribes," she replies.

The woman, named Zennie Ngwenya, is a tall and handsome Matabele, a tribe that broke off from the Zulus and entered the area that is now Zimbabwe in the 1800s.

"The Nigerians always stick in groups," she says.

"You never see a Nigerian on his own. It's clever maybe, because then the tsotsis can't get them and the police struggle to arrest them."

It is a cool first day of spring and Hillbrow feels relaxed and happy. It is the perfect time for a photograph A man wearing a brown jacket threatens to shoot if he is not given the camera.

The man and his accomplice sprint down the street as a police van drifts by.

"He was a Zimbabwean, I can tell from his accent," Ngwenya says. "People are desperate now, so they will steal."

Cities around South Africa especially the financial capital, Johannesburg, have become homes for immigrants mostly from Africa, who want to escape poverty and conflict in their countries.

Many work as gardeners and domestic workers. Some get jobs as carpenters and security guards. Others, driven by despair, become criminals.

But while the police in Hillbrow seem unperturbed by the Nigerians and Zimbabwean, illegal immigrants are often arrested and sent to the Lindela Repatriation Centre, 40km north west of Johannesburg.

Lindela, which can hold about 2000 deportees, is South Africa's only deportation centre for illegal immigrants.

It was opened in April 1997 and is built on a site that was first used as a hostel for Chinese migrants who came to mine Johannesburg's gold fields more than 100 years ago.

In the eight and half years Lindela has been open, some 600 000 illegal immigrants are said to have passed though its gates.

But the centre has had its share of criticism recently. Last week three senior officials were suspended at the camp after the death of two detainees.

A Lindela official denies any wrongdoing and says the immigrants died of natural causes. Many terminally ill people are sent to the facility and have to be admitted to the nearby Leratong Hospital, he says.

Lindlela described as "a torture chamber"

A recent article by a Johannesburg newspaper said that seven Zimbabwean clergymen who visited Lindela described the facility as a "torture chamber".

A Zimbabwean woman, who spent a night at Lindela, complained that she had to pay a bribe to be let out, even though she had South African citizenship documents.

Joe Gumede, a director at Lindela, says officials do not take bribes.

"Maybe in the past, but if anyone is caught taking a bribe they will be fired," he says.

On a tour of the facility, there are no visible signs of maltreatment of the detainees.

The immigrants are served three solid meals a day, usually porridge for breakfast and then chicken and potatoes or mince meat for lunch and dinner. Fruit is served with all meals.

Detainees are given a clean mattress and a blanket when they arrive.

There is also a resident doctor, who operates a very organised medicine dispensary. Outside the dispensary there is a short line of immigrants who have come for vitamins and headache tablets.

It costs R59.58 a day to hold an immigrant at Lindela.

Many of the immigrants complain about bureaucracy and that their time is being wasted, but when asked they do not have any other complaints.

"You need a facility like this. It is important for human rights," says Home Affairs spokesman Leslie Mashokwe.

"Before the immigrants would be put in normal jails."

Mashokwe says Lindela does not accept pregnant women, minors or people who are very ill.

"We tell the police to take them back to where they came from," he says.

Immigrants should not stay at Lindela for more than 30 days.

"Often we have no choice because the immigrants give us false names or lie to us about where they come from. We also have to wait for representatives from embassies to identify people from their country. This can take time"

Some detainees from far away are flown back to their countries, but others, mostly from Mozambique and Zimbabwe are taken back by train.

Mashokwe says many manage to jump out of the train while it is moving.

"By the time it gets to Zimbabwe or Mozambique, it is often half full," he says.

Mashokwe says it is impossible to effectively police South Africa's 8000km of borders.

"Our borders are very porous. Many of these guys will swim through rivers infested with crocodiles to get here. They are very determined. The only way to stop illegal immigrants is to encourage investment in African countries and for that you need peace and stability."

Another way to decrease the numbers of illegals is to sign visa agreements.

The number of Mozambicans at Lindela has dropped in recent months since the signing of a visa agreement. But this is said to be a long way off, especially with regard to Zimbabwe which is in economic and political turmoil.

Bertus Swanvelder, a unit leader at Lindela, says many of the detainees have amazing stories of how they got to South Africa.

"Some tell us stories of how they were charged by elephants and attacked by lions as they came across Kruger National Park," he says.

"The come in a group of 50 but only 15 survive. They have amazing stories. It breaks your heart sometimes."

But it is not just Africans, who are held at Lindela.

Nelson Ancco from Peru, was sent to Lindela after serving seven years in prison for smuggling cocaine into Johannesburg.

Ancco, 33, struggles to speak English but is fluent in Zulu and Afrikaans which he learned in prison in Johannesburg.

"I have a wife who has left me for another man, which I understand. But I cannot wait to see my four children," he says.

Annco has been at Lindela for one month. He is waiting for the Peruvian embassy to identify him and clear the way for his return.

Lindela's spokesman, Papa Leshababe, said many immigrants do not want to go home when their time comes.

"Some people have to go back to countries where there is conflict and shortages of food," he says.

"When their time to go comes we call them over the intercom, but they hide away."