Busisiwe Mkhwebane will replace popular Thuli Madonsela as the next public protector next weekend.

South African President Jacob Zuma approved a new anti-graft watchdog on Thursday, hours before the outgoing investigator will question him about allegations his wealthy business friends influenced political appointments.

Zuma signed off on parliament's choice of Busisiwe Mkhwebane as the next public protector, replacing Thuli Madonsela, whose high-profile investigation into improper state spending on Zuma's private home has won her popular respect. Her term ends next Saturday.

Madonsela will quiz Zuma on Thursday over accusations the Gupta family played a role in selecting cabinet members and used their relationship with the president to gain favour in terms of government tenders, payments and licenses. The Gupta family became household names in South Africa after deputy finance minister Mcebisi Jonas said they had offered to secure him his boss's job.

Mkhwebane, a lawyer who recently held a position at the State Security Agency, was nominated by 60 percent of lawmakers in a vote last month.

Opposition MPs from the Democratic Alliance voted against her appointment saying she had connections to Zuma. But the Economic Freedom Fighters, who have been fiercely anti-Zuma under the leadership of the president's former protégé Julius Malema, supported Mkhwebane's nomination.