The announcement was the first move against the Gupta family that is accused of corrupt dealings with Zuma, including allegations it profited from lucrative government contracts and chose ministerial appointments.
The local company, Trillian, was controlled by an associate of the Guptas at the time of the allegations in 2015 and 2016.
McKinsey and Trillian were paid for a contract advising state power monopoly Eskom.
“The first order… refers to McKinsey and Trillian, that’s 1.6 billion rand ($130 million, 105 million euros) we are asking to be paid back, that process is related to work they did with Eskom,” Knorx Molelle, head of the National Prosecuting Authority’s (NPA) asset forfeiture unit, told the eNCA news broadcaster.
The NPA denied that any arrests were imminent, but the opposition Democratic Alliance party called for border posts and airports to be put on alert to stop the Gupta family from fleeing the country.
Pressure on the Gupta brothers, originally from India, increased after Cyril Ramaphosa was in December elected as the new head of the ruling ANC party rather than Zuma’s preferred candidate and ex-wife Nkosazana Dlamini-Zuma.
Ramaphosa has pledged to “restore the credibility” of the ANC after the spate of corruption scandals involving Zuma.
Zuma could remain as national president until next year, but he faces being forced out of office by the party to be replaced by Ramaphosa.
Zuma and the Guptas deny any wrongdoing.
McKinsey has already announced it would return the fee it earned from the Eskom contract.
The scandal has added to the ANC’s woes ahead of the general election due in 2019 when the party could lose power for the first time since the 1994 post-apartheid polls.