Parts of the crucial N3 highway which connects Durban to the economic heartland of Gauteng province have been blocked.
President Cyril Ramaphosa has visited the area and pledged to help.
"Even though your hearts are in pain, we're here for you," the Reuters news agency quotes him as saying.
He also described the disaster as a force of nature, which some have disagreed with. They blame poor drainage and badly built houses in low-lying areas for the high death toll.
Mxolisi Kaunda, mayor of the area's biggest city Durban, has denied that poor drainage is to blame, saying the scale of the flood was unexpected.
Scenes of destruction are still evident throughout the area. Some of the roads to the port of Durban are impassable after the swollen river washed mud and debris onto the roads. Operations at the port have now been suspended.
In an industrial area called the Bluff, which forms part of the port, the BBC witnessed cars overturned on the road, or crushed by debris. Companies are using water pumps to drain the water from their premises.
Ron Naidoo, a community pastor in the town of Tongaat, told the BBC he had been kept awake through the night by the rising floodwaters and had seen police drag a car out of the river with a body inside.
"It was traumatic because it is the first time that we have seen the river rise so high here," he continued.
