JOHANNESBURG - South African President Cyril Ramaphosa has ordered the country's Special Investigating Unit (SIU) to probe allegations of maladministration at state run-power utility Eskom and logistics group Transnet, the government said on Friday.

Ramaphosa, who replaced former president Jacob Zuma in February, has made the fight against corruption a key plank of his administration as he seeks to restore investor confidence after the scandal-plagued Zuma era.

The announcement of the probe was published in the government gazette.

The SIU, which investigates malpractice in state institutions, state assets and public money, will investigate among other things, "unauthorised, irregular or fruitless and wasteful expenditure" incurred by Eskom and Transnet.

Eskom has been embroiled in allegations of corruption relating to a 1.6 billion rand ($130 million) contract that global consultancy McKinsey worked on with Trillian, a local company that was then controlled by Gupta family who are accused of using their access to Zuma to win state contracts.