World football's governing body, responding to criticism of the empty seats at many early games, added average attendance was above Germany four years ago and was the second highest behind the World Cup in the United States in 1994.
There were empty rows of seats in sections reserved for corporate fans at Soccer City stadium in Johannesburg for Monday's Group E opener between the Netherlands and Denmark and swathes of empty seats have blighted other matches.
Soccer City has a World Cup capacity of 88,000 with the attendance for Monday's match given as 83,465.
There were 10,955 empty seats at Saturday's match between South Korea and Greece at Port Elizabeth and the official attendance at the Algeria-Slovenia match in Polokwane on Sunday was 30,325, out of a capacity of 41,733.
FIFA spokesman Nicolas Maingot told a media briefing: "We have made some group sales and those group sales are for large organisations and companies. They did sell, but some ticket holders have not come.
"We are not talking about unsold tickets, we are talking about sold tickets which have not been occupied.
Currently South Africa is second behind US '94 for average attendances, with the completed 52 games in the United States producing an average attendance of 68,991 - and a total attendance figure of 3.59 million spectators.
Maingot continued: "What we have realised in our investigations is that some ticket holders, including international ticket holders have not turned up.
"When you look at the issue of the empty seats, which we clearly recognise, you need to look at the bigger picture.
"The bigger picture is that we have now the second highest attendance after the USA in 1994."
