30 000 relatively wealthy spectators a week, every week for nine months of the year.

That's the crowd each of the country's newly-built stadiums has to attract to be self-sustainable after next year's World Cup, says Cape Chamber of Commerce and Industry executive Albert Schuitmaker.

Schuitmaker says it is unlikely that the vast investment in World Cup stadiums will ever produce acceptable returns.

"It has not done so in many countries which have hosted World Cups and Olympic Games. Indeed some stadiums have been demolished soon after the event."

Schuitmaker said stadiums only pay for themselves in situations where they bring in crowds of 30 000 affluent supporters a week, every week for nine months of the year, and where they are subsidised by commercial developments under the grandstands.