South Africa's health minister said on Tuesday that government advisers had grouped Covid-19 vaccines into three groups and those considered for "immediate use" were the Johnson & Johnson (J&J), Pfizer and Moderna shots.
The country started rolling out the J&J vaccine in a research study targeting healthcare workers last week and hopes to receive Pfizer doses in the coming months.
It has paused AstraZeneca vaccinations because of a small trial showing the British company's shot offered minimal protection against mild to moderate illness caused by the dominant local coronavirus variant.
Health Minister Zweli Mkhize said the government had placed "huge orders on J&J and Pfizer which will be finalised in the next few days and announced when concluded", adding that discussions with Moderna were ongoing.
Mkhize said the Ministerial Advisory Committee on vaccines had placed Russia's Sputnik V vaccine and alternatives from China's Sinopharm and Sinovac in a second group where South Africa is interested but requires more technical information.
A third group where vaccines "may not be suitable for immediate use in South Africa" includes the AstraZeneca and Novavax vaccines.
South Africa has recorded almost half of the Covid-19 deaths and over a third of confirmed infections in all of Africa, but has lagged wealthier nations in launching its immunisation campaign.
The government plans to vaccinate 40 million people, or two-thirds of the population.