Surfers in South Australia say they have witnessed a pod of killer whales attacking a school of more than 100 dolphins.

One of the surfers on lower Eyre Peninsula, Jamie Kidney, says the attack was an incredible sight.

"Chaos, you just saw monstrous amounts of white water and then a dolphin would go flying in the air, a killer whale would jump out of the water, grab it and body slam it," he said.

"They were just jumping out the water attacking dolphins and it was just chaos really.

"Normally what you see great whites do to seals and that."

Surfer Anton Storey also watched in awe as the whales flipped dolphins into the air.

"When the killer whales turned up a whole heap of dolphins started shooting towards the shallows there," he said.

"Next thing you know we look up the back and these killer whales were just ramming dolphins out of the water and then grabbing them, and this just kept going on and on and on. It was unreal."

The South Australian Museum's curator of mammals, Cath Kemper, says the reports of killer whales attacking dolphins are the first of their kind in SA.

"There have been a couple of reports from Tasmania of killer whales herding up common dolphins into a bay, I don't think they actually were observed to kill any at that time - whether they were just trying to scare the living daylights out of them or whether they really did want to eat them, but they eat mammals, they eat seals and they will eat dolphins," she said.