South African President Cyril Ramaphosa is receiving treatment for mild Covid-19 symptoms after testing positive on Sunday, the office of the presidency said in a statement.

He has delegated all responsibilities to Deputy President David Mabuza for the next week.

Ramaphosa "started feeling unwell after leaving the State Memorial Service in honour of former Deputy President FW de Klerk in Cape Town earlier today," the presidency statement said.

He is, however, "in good spirits" and is being monitored by the South African Military Health Service of the South African National Defence Force.

"President Ramaphosa says his own infection serves as a caution to all people in the country to be vaccinated and remain vigilant against exposure. Vaccination remains the best protection against severe illness and hospitalisation," the statement said.

South Africa, where scientists identified the new Omicron variant, has recently entered its fourth wave of the pandemic.

Just over 25% of the country has been fully vaccinated, with an additional 5% partially vaccinated, according to CNN's global vaccine tracker.

Ramaphosa, who is fully vaccinated, recently returned from a trip to West Africa.

He tested negative for Covid-19 upon his return to Johannesburg on December 8, according to his office.

The President is now in self-isolation in Cape Town.