Among other restrictions announced late on Monday, indoor and outdoor gatherings will be banned and a curfew will be enforced from 9pm (19:00 GMT) to 6am (04:00 GMT).
Only workers with permits, including medical and security personnel or emergency staff, may move during the curfew.
“From now on, it is compulsory for every person to wear a mask in a public space. A person who does not wear a cloth mask covering over the nose and mouth in a public place will be committing an offence,” said President Cyril Ramaphosa in a televised address.
“On conviction, they will be liable to a fine or to imprisonment for a period not exceeding six months, or to both a fine and imprisonment.”
Ramaphosa also announced that non-essential establishments, including shops, restaurants, bars and all cultural venues, must close at 8pm (18:00 GMT), while the sale of alcohol from retail outlets and on-site consumption of alcohol will not be permitted.
The new rules will last for 14 days and they may be reviewed within the next few weeks if they see a sustained decline in infections and hospital admissions, he added.
On Sunday, South Africa’s health ministry reported a grim milestone of one million infections – the highest figure on the continent.
So far, the novel virus has killed more than 27,000 people in South Africa.
The sweeping restrictions were imposed after authorities confirmed a new coronavirus variant has been found circulating in the country.
The variant appears to be focused in the south and southeast of the country and has been dominating findings from samples collected since October.
“It was the doctors and the health workers who were calling for these restrictions,” said Al Jazeera’s Haru Mutasa, reporting from Port Elizabeth which has now turned into the country’s coronavirus hotspot.
“They were saying they are really not surprised about the rise of infections, what surprised them is how quickly it happened,” she added.
The outbreak in the worst-hit country in Africa appears to be accelerating with the one million mark crossed nine days after the country reported 900,000 cases.Several hospitals and medical centres have reported that their wards are overflowing with coronavirus patients with many healthcare workers cancelling their holidays to tackle the huge influx.
According to Mutasa, people have failed to comply with basic restrictions, travelling around the country, visiting friends and family without wearing masks or practicing social distancing.
“In the Eastern Cape province […] people tell you they had up to seven people in the family who’ve died to COVID. You hear stories of people who attended funerals and became sick,” she said.