Heavy rains are expected in six provinces this weekend, the SA Weather Services said on Friday.
Forecaster Ezekiel Sebego said heavy rains were expected in KwaZulu-Natal, Gauteng, the eastern part of North West, eastern Free State, Limpopo and Mpumalanga.
"Flooding is possible to due to water levels rising and rivers overflowing."
He said heavy rains were expected from Friday night until Sunday. In Mpumalanga and Limpopo, heavy rains were expected to continue until Monday.
Ekurhuleni metro disaster and emergency management services said they were ready to handle emergency situations.
"Our various teams including [the] disaster management centre, the emergency services and municipal engineers are on stand-by ready to respond to life and non-life threatening situations from today (Friday) and will be on the watch throughout the weekend," said spokesperson Bafana Mazibuko.
"We appeal for our communities to heed the various warnings issued by disaster and emergency services in this regard, and encourage them to take practical steps to minimise the impact of heavy rains."
He said residents should refrain from settling in low-lying areas.
"Residents should use sandbags to channels flash flood water away from the residential structures, dig canals that take water away from residential structures and also avoid crossing on foot or [in a] vehicle any low-lying bridges and roads."