Twelve people have died in flooding caused by torrential rain on South Africa's eastern coast, local authorities said on Monday.

In Eastern Cape province, "the death toll is currently sitting at seven," a spokesperson from Nelson Mandela Bay municipality, at the heart of the floods, told AFP.

Near the port city of Durban in KwaZulu-Natal province, "five people have sadly lost their lives in the eThekwini Metro, which has been hardest hit, and dozens of people are being treated for injuries in health care facilities," the provincial government said in a statement.