President Cyril Ramaphosa has announced new tougher coronavirus restrictions, a day after South Africa recorded more than one million Covid-19 cases.
Indoor and outdoor gatherings will be banned, a curfew introduced from 21:00 to 06:00, and alcohol sales prohibited.
Mr Ramaphosa said the country was at an extremely dangerous point in the pandemic and action had to be taken.
Recently authorities confirmed a new, faster-spreading variant of the virus had been detected in South Africa.
Some hospitals and medical centres have reported a huge rise in admissions, putting a heavy strain on resources.
In a televised speech, Mr Ramaphosa said the new 501.V2 variant was now well established in South Africa, and the recent rise in cases was a “cause for great alarm”.
“We have simply let our guard down,” said the president.
He added that the new measures would come into effect at midnight on Monday (22:00 GMT) and last at least until 15 January.
He said gatherings excepts for funerals and a few other limited exceptions would be banned, no-one would be able to leave their homes between 21:00 and 6:00 without a permit, and all shops, bars and other venues would have to close by 20:00.
All alcohol sales would also be banned, and every individual who failed to wear a mask in public places would face possible fines or imprisonment, he added.
On Sunday South Africa became the first country in Africa to pass a million Covid-19 cases, with 1,004,413 infections and 26,735 deaths since the outbreak began in March.
Last week, it recorded a daily average of 11,700 new infections – a rise of 39% on the previous week – and from Wednesday to Friday, the daily number of new cases was above 14,000.
The 501.V2 variant is believed to be driving the surge in infections. It was identified by a network of South African scientists in the Eastern Cape province and then rapidly spread to other parts of the country.