JOHANNESBURG (Reuters) - South African President Jacob Zuma said on Thursday he has full confidence in Finance Minister Pravin Gordhan, who is under police investigation over a suspected spy unit at the tax service.

Zuma said he could not intervene in the investigations despite the negative impact the probe has caused on the economy, according to a statement released by the presidency.

The rand, which had tumbled since Tuesday in response to the investigation, extended gains to 1.3 percent after Zuma's statement.

(Reporting by James Macharia; editing by John Stonestreet)