FIFA said Monday it was investigating why there had been empty seats at some of the World Cup matches in South Africa.

FIFA spokesman Nicolas Maingot confirmed there were unfilled seats at the Algeria v Slovenia match in Polokwane on Sunday and "to some extent" in Pretoria for the Serbia v Ghana clash on the same day.

On Monday there were banks of empty white seats in Bloemfontein's Free State stadium for the clash between Japan and Cameroon, with a crowd of just 30,600 in a ground that can seat nearly 41,000.

"Of course it is not nice to see empty seats at a World Cup stadium but if you want to look at the issue you have to look at the issue in its globality," the spokesman said.

"The bigger picture is that the attendance average is still very high, above 50,000 people per game... and you cannot draw conclusions after eight games.

"It is far too premature, you can only draw conclusions at the end of the competition."

Asked why tickets were not given away to fill stadiums, Maingot said the empty seats concerned tickets which had been sold but whose holders had failed to attend the match.

"We are not talking about unsold tickets, we are talking about sold tickets which are not filled," he said.

Japan coach Takeshi Okada acknowledged the issue of empty seats at matches but said "they are not a big issue for us."

"Empty seats have been observed during some other matches I have seen on TV," he said.

"As Japan is far away from South Africa geographically speaking perhaps some supporters were not able to come from Japan," he added.

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