Foreigners will inject 13 billion rand (1.77 billion dollars) into South Africa's economy during the World Cup, helping the soccer spectacular boost economic growth by 0.5 percentage points.

The estimated gross economic impact for South Africa, including indirect spending and infrastructure built over the past four years, will be 93 billion rand, according to a study by the accounting firm Grant Thornton.

But the bulk of this is internal government spending.

Gillian Saunders, who led the study, told journalists and economists on Wednesday that less foreign fans were expected to come than previously thought, but those that do would spend more compared to other tournaments such as Germany in 2006.

With 50 days to go before kick-off, football fever is growing in South Africa but the global economic crisis, the tournament's high cost as a long haul destination and fears of violent crimes have reduced the numbers of foreign fans.

'We have revised the figures post the world-wide recession and major ticket sales phases, and some of the numbers are encouraging,' Grant Thornton's Gillian Saunders said, presenting the study on the World Cup's economic effect.

Grant Thornton has conducted in-depth research into the impact of the World Cup for South Africa, and its reports are seen as authoritative by other analysts.