Tourists on a shark cage diving trip were treated to the rare sight of a great white shark being slammed into and killed by a family of killer whales.

The rare fight between two top predators of the marine world was seen on Monday in South Australia off the coast of the Lower Eyre Peninsula.

The shark was eventually killed under the surface.

The family group of orcas, included two calves being taught the rudiments of attack and kill.

"The intelligence behind it was just fantastic. It was definitely the highlight of my career. Not much is probably going to top this," said crew member and marine biologist Gina Dickinson.

South Australian Museum senior researcher Catherine Kemper said it was the first time such behaviour has been seen of the orcas in the region.

According to the charter operator, attacks by orcas in other places in the world had resulted in sharks dispersing far and wide, causing damage to the cage diving season.

Orcas, or killer whales, are the largest dolphins and apex predators at the top of the food chain at sea.

They feast on marine mammals such as seals, sea lions, and even whales.

They hunt in deadly pods, family groups of up to 40 individuals. Orcas can be recognised by their distinctive black-and-white colouring and are very intelligent creatures.

Weighing up to 5,443 kg and growing up to 23 to 32 feet (7 to 9.7 metres), the orca population is unknown according to the IUCN.

Unlike the fierce orcas, the great white shark, which has been the most feared marine animal, a la Jaws, is not really aggressive as much as curious, says recent research.

Great whites grow to an average of 15 feet (4.6 metres) in length and are listed as an endangered species.