"It is stretching our resources and our resolve to their limits," he said.
"As we head towards the peak of infections, it is vital that we do not burden our clinics and hospitals with alcohol-related injuries that could have been avoided," Ramaphosa said in a televised address to the nation.
"We have therefore decided that in order to conserve hospital capacity, the sale, dispensing, and distribution of alcohol will be suspended with immediate effect."
South Africa's first booze ban, implemented in March, was lifted on 1 June.
But on Sunday, Ramaphosa rescinded the move, saying "there is now clear evidence that the resumption of alcohol sales has resulted in substantial pressure being put on hospitals, including trauma and ICU units, due to motor vehicle accidents, violence as well as trauma that is alcohol-induced."
He also ordered a curfew from 9pm until 4am starting on Monday.
Ramaphosa also outlawed family visits and social events that have been blamed for helping the virus spread.
His administration would from now tighten the regulations on the mandatory wearing of face masks.
Ramaphosa said the government was ramping up the healthcare system where there are 28,000 hospital beds reserved for coronavirus patients.
But the system is desperately short of staff, with at least 12,000 more mostly nurses, doctors and physiotherapists still required.
"We have heard of instances where people who are infected have been turned away from health facilities due to a lack of beds or essential supplies. This is deeply worrying," he said.
Health experts have predicted that South Africa's coronavirus outbreak will peak between July and November and is projected to claim at least 40,000 lives.
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The NICD has another Clinician Hotline to improve #COVID19 communication and support for healthcare providers. The Clinician Hotline is 0800 11 1131, operating 24 hrs. The Public Hotline is 0800 029 999 also operating 24hrs.