SYDNEY, Dec 17, 2009 (AFP) - Australian surfers Friday told of their horror as they watched a pod of killer whales attack a large group of dolphins, throwing them into the air and leaping to catch them.

Jamie Kidney said he was surfing off southern Australia's Eyre Peninsula with his friend Anton Storey when the ocean erupted into a seething mass of white water and "all hell broke loose".

"(It was) just chaos, you saw monstrous amounts of white water and then dolphins go flying up in the air, a killer whale would jump out of the water, grab it and body-slam it," Kidney told state radio.

"We look up out the back and these killer whales are just ramming dolphins out of the water and grabbing them, and this just kept going on and on and on, it was unreal," added Storey.

The pair estimated there were up to 100 dolphins under attack, and Kidney said the whales appeared to be toying with the mammals for fun before killing and eating them.

South Australian biologist Cath Kemper said it was "on the unusual side" to see killer whales attack dolphins so close to shore.

"They might have come in initially to look for snapper and maybe there were some dolphins around," Kemper told AFP.

"We've certainly had other reports of killer whales attacking seals and things but not necessarily dolphins.

Sometimes called "wolves of the sea", killer whales are top-order predators that eat anything from squid to larger marine mammals, she added.