The total value of rigged construction industry projects being investigated by the Competition Commission is much higher than expected at R47 billion, Economic Development Minister Ebrahim Patel said on Tuesday.
Speaking in the National Assembly during debate on his budget vote, Patel said 300 cases of collusion and price-fixing had been identified by the commission.
"Eighteen construction companies, including the top six firms, have now confessed and are in discussions on settlements with the competition authorities," said Patel.
The CC was looking into various projects, including the building of Soccer City in Johannesburg and the Cape Town Stadium in Cape Town.
"Private sector collusion and price-fixing cost the state many billions of rands in previous infrastructure projects, including the 2010 World Cup stadia," Patel said.
Government was determined to eradicate cartels which used taxpayers' money to line their own pockets.
"The competition probes extend wider than infrastructure and include input costs across the economy, to improve competitiveness and reduce costs for consumers," Patel said.
The commission has previously indicated it will conclude settlement talks with construction companies who have admitted guilt by May.
These talks could lead to fines worth several billion rand being issued, following consent agreements between the CC and the companies being approved by the Competition Tribunal, by June or July.