ANC chairwoman Baleka Mbete will replace Max Sisulu as Speaker of the National Assembly, ruling party secretary general Gwede Mantashe said on Tuesday.

Speaking shortly after the ANC's first caucus meeting of the fifth democratic Parliament, Mantashe said: "Comrade Baleka Mbete will be the Speaker of Parliament. Lechesa Tsenoli will be the deputy speaker."

The official election of the Speaker would take place after MPs were sworn in in the National Assembly on Wednesday.

Tsenoli is expected to replace Nomaindia Mfeketo as deputy speaker.

Stone Sizani would remain Chief Whip and Doris Dlakude his deputy.

Mantashe denied that Sisulu was being punished for establishing an ad hoc committee to probe President Jacob Zuma's reply to the Public Protector's damning report on Nkandla.

The Sunday Times reported last month that Sisulu had been summoned to ANC headquarters Luthuli House to explain why he set up the committee, following a complaint by Mfeketo.

"I don't know what informs this assumption," Mantashe said.

"Max was doing his job. The ANC should be happy and satisfied with a Speaker who does his work."