Guesstimating the number of undocumented migrants living in South Africa is like asking, "How long is a piece of string?" and the answer is - no one knows.
The Minister of Home Affairs, Nkosazana Dlamini-Zuma, when asked how many undocumented migrants were living in South Africa at a parliamentary media briefing on 12 November in the port city of Cape Town, answered candidly: "I don't know. If somebody's here illegally, how do I know they are here? I do not know - that's an honest answer."
The home affairs website cites a 1996 study by the Human Sciences Research Council, which estimated that between 2.5 million and 4.1 million undocumented migrants were living in South Africa, but that survey was conducted before neighbouring Zimbabwe's economy collapsed.
It is thought that since 2000 more than 3 million Zimbabweans have fled the country's economic freefall and political violence, many to South Africa - the continent's economic powerhouse - and others to countries as far afield as the UK and Australia.
The SA Police Services (SAPS) in its latest (2008/09) annual report said, "According to various estimates, the number of undocumented immigrants in South Africa may vary between three and six million people."
If the upper figure of 6 million is accurate - although other estimates have put the number at 10 million - then about 11 percent of people living in South Africa are undocumented.
A survey released on 13 November by the South African Institute of Race Relations (SAIRR), South Africa Survey 2008/2009 - Demographics, estimates the country's population at 49.32 million.
|It would be a very useful thing for the country to know how many people are here, but home affairs inefficiencies are dire and deeply engrained|
Marco MacFarlane, SAIRR's head of research, told IRIN he had heard of estimates of between 500,000 and 2 million undocumented migrants, but their numbers were not included in the demographic survey because "undocumented migrants are undocumented".
"Everyone has a methodology and it all looks like a best guess ... the SAPS figure of 3 to 6 million [undocumented migrants] means that there could be 3 million people who may or may not be here," MacFarlane told IRIN.
"It would be a very useful thing for the country to know how many people are here, but home affairs inefficiencies are dire and deeply engrained; to know how many people are here requires home affairs to become less corrupt and more efficient."
The government of President Jacob Zuma is discussing the introduction of a permit for undocumented migrants.
"What I can tell you is that [in 2008] there were about 110,000 applications for asylum. Only 10,000 were agreed to as genuine asylum seekers and those were then given refugee status," minister Dlamini-Zuma told the parliamentary media briefing, according to local news reports.
"The rest would have had to leave by either deportation or voluntarily ... But as for those who don't turn up at our offices, either as asylum-seekers or permit-seekers or anything, it's very difficult [for me to] give you a figure for that."