An arrest warrant has been issued for the secretary general of South Africa's ruling African National Congress, Ace Magashule, a provincial spokeswoman for the country's elite police unit the Hawks said on Tuesday.

"He hasn't been arrested as yet but the warrant has been signed... on charges of corruption in the asbestos case," said Lynda Steyn, spokesperson for the Hawks in the Free State, where the case took place.

That was a reference to a contract awarded while Magashule was premier of the Free State province.