One of Durban's main highways has been closed following flooding, the city's metro police said on Monday.

The M4 northern freeway between Umhlanga and Sibaya was closed, Durban Metro Police spokesperson Senior Superintendent Parbhoo Sewpersad said.

"This is as a result of flooding. It will be closed for an unknown period of time. We have reached out to the Department of Transport's engineers to assess the damage so far. I don't think the road will be opened today."

He said alternate routes were the M41, N2 and the R102.

Many other parts of the city - including Verulam, Amanzimtoti, Chatsworth and other low lying areas - were affected by the rains.

Pictures and videos circulating online show extensive damage to property and vehicles.

Rescue Care spokesperson Garrith Jamieson cautioned motorists to drive carefully.

"There is flooding on multiple roadways. Rescue services and ambulances are on standby."

Disaster management teams in the province were placed on high alert on Sunday, following reports of severe thunderstorms.

Teams were placed on alert after the South African Weather Service (SAWS) indicated a strong possibility of severe thunderstorms that could lead to localised flooding in large parts of the province.

Recently, four people were killed after a lightning strike in Mkhuze in northern KwaZulu-Natal.