There were just 4,456 new cases in the past 24 hours, he said. This is down from the 5,378 new infections announced on Tuesday night.
It means that there are now 521,318 confirmed cases of Covid-19 across SA.
The latest figures are based on just 19,507 tests, significantly fewer than have typically been conducted in 24-hour cycles over the past few weeks. In total, 3,078,202 tests have been conducted across the country to date.
Mkhize on Wednesday night also reported 345 new fatalities, taking the national Covid-19 death toll to 8,884.
Of these, 116 were recorded in Gauteng, 97 in the Western Cape, 89 in KwaZulu-Natal and 43 in the Eastern Cape.
SA's recovery rate has edged closer towards 70%, with Mkhize confirming 363,751 recoveries - a rate of 69.8%.