South Africa on Sunday further tightened COVID-19 restrictions for 14 days to combat the more transmissible delta variant that has already been reported in five of its nine provinces.

Making the announcement, President Cyril Ramaphosa said the variant, first reported in India, has been detected in the Eastern Cape, Free State, Gauteng, KwaZulu-Natal and Western Cape.

"The evidence we have is that the delta variant is rapidly displacing the beta variant, which has been dominant in our country until now. We are concerned about the rapid spread of this variant because it is thought to be twice as contagious as the beta variant," Ramaphosa said.

He said there is an emerging scientific evidence that people previously infected with the beta variant do not have full protection against the delta variant, and may be re-infected.

Ramaphosa said as of Sunday, the seven-day average of new daily cases nationally had overtaken the peak of the first wave in July last year, and will soon overtake the peak of the second wave experienced in January.

South Africa, the most affected country in the continent in terms of infection cases and deaths, is currently in the grip of a devastating wave that seems like it will be worse than the previous ones.

"The peak of this third wave looks set to be higher than the previous two. The first wave lasted 15 weeks. The second wave lasted nine weeks. We don't know how long this one will last, but indications are that it could last longer," Ramaphosa said.

He said public health facilities in several provinces are stretched to their limits, and private facilities are also buckling under the strain.

Noting that the existing containment measures in place are not enough to cope with the speed and scale of new infections, the president announced new measures effective June 28 to July 11.

In the new measures, all gatherings, whether indoor or outdoor, are banned; attendance to funerals and cremations will be limited to 50 people; sale of alcohol is banned; and a night curfew will be observed from 9 pm to 4 am. Schools will also start closing from Wednesday to Friday.

"Most businesses will continue to operate at full capacity and should not be affected. Our focus is on limiting social contacts while preserving the economy," Ramaphosa said.

"I want to emphasize that it remains mandatory for every person to wear a face mask that always covers their nose and mouth when in public spaces. It is a criminal offence not to do so."

As of Monday in the morning hours, South Africa had reported 1,928,897 infection cases and 59,900 deaths.

The country has so far vaccinated nearly 2.7 million of its 60 million population.

On Thursday, South Africa received 1.2 million doses of the Johnson & Johnson vaccine and 1.4 million doses of the Pfizer vaccine through the Covax facility.