About 100 000 doses of Pfizer's Covid-19 vaccine are at risk of being destroyed by the end of this month due to slow uptake by citizens, South African health authorities said on Friday.

South Africa has recorded the most coronavirus infections and deaths on the African continent, however inoculations have slowed and the country has ample vaccine stocks of about 25-million doses.

"There is a risk that just over 100 000 or so doses which will expire by end of March ... may have to be discarded. It will be a sad day if significant volumes of doses can end up being discarded. We hope it will not reach that stage," Health Minister Joe Phaahla told an online news conference.

He said the department was trying to ramp up inoculations to save the vaccine doses from being discarded. South Africa has so far fully vaccinated around 43% of its 40-million adults.

South Africa's vaccination campaign, using the Johnson & Johnson (J&J) and Pfizer vaccines, got off to a slow start due to difficulties securing early supplies but more recently it has been dogged by hesitancy. Last month the country changed its Covid-19 vaccination rules in an effort to encourage more people to get jabs.