A giant shark believed to be up to 6m long almost bit a great white shark in half off the coast of an Australian island.

Two bites were taken out of the 3m white pointer by another great white, which is believed to be 1.5m longer than the creature at the centre of Steven Spielberg's Jaws, Australia's Daily Telegraph reports.

Ashton Smith, a 19-year-old surfer, said: "Whatever attacked and took chunks out of this big shark must be massive.

"I've heard about the big one that's lurking out there somewhere. We're all being very, very cautious."

Jeff Krause of Queensland Fisheries added: "It certainly opened up my eyes. I mean the shark that was caught is a substantial shark in itself."

The injured great white was still alive when it was dragged on to a boat near Deadman's Beach off north Stradbroke Island.