South African police raided on Monday the compound of former president Jacob Zuma's allies the Guptas, who were accused two years ago in a report by a corruption watchdog of using their influence to gain control of state companies and contracts.

The National Prosecuting Authority's spokesperson Luvuyo Mfaku said the raid was part of an investigation into fraud at a state-backed dairy project in the Free State province.

The three Gupta brothers, accused by the public anti-graft watchdog of using their friendship with Zuma to influence policy and amass wealth, have denied any wrongdoing, as has Zuma. The Guptas have also denied any wrongdoing in the dairy scandal.