South Africa will offer booster doses of the Pfizer and Johnson & Johnson (J&J) Covid-19 vaccines as the Omicron coronavirus variant drives daily infections towards record highs.

Pfizer boosters will be available to people six months after they receive their second dose, with the first people becoming eligible late this month, the South Africa health department's deputy-director general, Nicholas Crisp, told a news conference.

J&J boosters, already available to health workers in a research study, will be rolled out to the general population soon, he added.

South Africa reported more than 22 000 new Covid-19 cases on Thursday, a record during a fourth wave of infections driven by the Omicron variant but still below a peak of more than 26 000 daily cases during the third wave driven by the Delta variant.

Addressing the same news conference, Health Minister Joe Phaahla said there were positive signs from early hospital data showing that Omicron appears to be causing mainly mild infections.

Glenda Gray, president of the South African Medical Research Council, said there were far more unvaccinated people among current hospital admissions.

On the Pfizer vaccine, she said: "We are seeing this vaccine is maintaining effectiveness. It may be slightly reduced, but we are seeing effectiveness being maintained for hospital admissions and that is very encouraging."