Gupta family associates have been accused of scoring billions of rands in alleged kickbacks to help a Chinese firm win lucrative Transnet tenders.
The revelations were made by the Daily Maverick and the amaBhungane Centre for Investigative Journalism on Thursday.
The allegations centre around a multi-billion rand contract won by Chinese firm CSR (Hong Kong) Co Ltd to supply locomotives to Transnet.
CSR (Hong Kong) was a subsidiary of China South Rail (CSR)‚ which won a tender to supply 359 locomotives to Transnet in 2014.
CSR contracted Gupta-linked Tequesta Group Ltd as a consultant‚ the two media outlets reported in an article published on EWN.
According to the agreement‚ Tequesta would earn a 21% cut of every deal gained by CSR. That amounted to around R5.3 billion since 2014‚ the Daily Maverick and amaBhungane said.
The report also detailed how the appointment of Malusi Gigaba as public enterprises minister in 2010 allegedly helped to entrench the influence of the Gupta family at Transnet.
Gigaba‚ who later moved to the home affairs portfolio and later finance‚ appointed Iqbal Sharma‚ who is close to the Guptas‚ to the Transnet board‚ where he oversaw procurement.
He also appointed Brian Molefe as Transnet chief executive in 2011 before his stint at Eskom and in parliament. Molefe was last year implicated in allegations of state capture surrounding the Guptas.
The Sunday Times reported on Tuesday that leaked emails showed how a former Gigaba adviser had done favours for the Guptas while at home affairs‚ although he denied any impropriety.
Gigaba has denied any involvement in state capture.