Nineteen pilot whales beached at Noordhoek Beach in Cape Town on Sunday morning, the city said.
Five of the whales had died, said the city's disaster management centre spokesman Wilfred Solomons-Johannes.
Police, sea rescue and other services were on scene trying to hose down the 14 surviving whales.
National Sea Rescue Institute spokesman Craig Lambinon said attempts were being made to help rescue the surviving whales.
"The option being looked at, if possible, is to try and refloat them, or to have them driven to the naval base in Simonstown and have them taken out to sea," he said.
"At this stage we are keeping them alive on the beach using water and blankets."
Lambinon appealed to the public to stay away from the beach as there were more than enough personnel on the scene.
The incident was also trending on Twitter.
Cape Times photographer Michael Walker tweeted that a tractor was used to remove whale carcasses from the beach. He also posted pictures. Tweeters said the beach had been closed to the public.
Marine biologists do not fully understand why whales beach but there are many theories.
KwaZulu-Natal Sharks Board head of operations Mike Anderson-Reade said one of the theories was that when one of the
leaders of the pod gets caught in shallow water, so do the others.
"And then they get disorientated and find their way to shore," he said.
Another theory was that when one of the lead whales gets ill, it beaches and the others follow.
"But these are all just theories, the reason is still unknown."
Scientific American on its website said some environmental activists had suggested that mass strandings of dolphins, whales, and other marine mammals were as a result of human impacts of pollution, shipping noise and, in some cases, military sonar.
- Sapa
