More than 35,000 people including several African heads of state are expected to attend the ceremony at a rugby stadium in the capital Pretoria.

Ramaphosa's speech will set the tone for his new administration, according to the president's spokeswoman Khusela Diko.

She said Ramaphosa will call for national unity, speak about job creation and reassert South Africa's role as an important voice on the continent.

Ramaphosa has promised a "new dawn" for the country since taking over from Jacob Zuma, who resigned in February 2018 amid ongoing corruption scandals.

The 66-year-old, who was Zuma's deputy from 2014, has a tough job ahead of him at the helm of a country with high rates of crime and unemployment as well as collapsing public services and an ailing economy.

On Wednesday, Ramaphosa was formally elected to South Africa's highest office.

Parliamentarians gave him the official mandate during an election in the National Assembly, which is responsible for choosing the South African president.

Ramaphosa's election came after the ANC won the May 8 polls with 57.5 per cent of the vote.

Australian Associated Press