South African-based platinum mining companies have expressed disappointment at the government's decision to charge royalties on revenue rather than profit.

Under the planned Mining Royalty Bill scheduled for 2009 a royalty of four per cent will be charged on platinum, eight per cent on diamonds and three per cent on gold.

The investment bank Investec told Business Weekly that the bill was 'not encouraging' for the mining industry, which stood to lose R264 billion in future income if it is introduced in its current form.

Along with mining firms, Investec stressed that the bill required further clarification, while also warning it had the potential to affect empowerment moves.

'Such uncertainty can create disinvestment and lead to capital flight as international investors look elsewhere in Africa for opportunities,' said Eric Lilford of Investec.

The government's Budget Review stated it is aware of the 'potential adverse impact on investment, employment and output' from the bill, explaining that it is still under review.

Finance director at Impala Platinum, David Brown, suggested that there was too little detail in the bill to comment.