A free-diver in Australia had a close encounter with a killer shark recently while swimming off the coast of Martin Island in New South Wales, Australia. The incident took place on 13 January when Callum Stewart and his diving companions were spotting seals.

The 28-year-old felt a bump against his back and thinking it was one of the mammals, turned around only to recognise it as a great white.

"I turned around to have a look and that's when I saw it was a shark," Stewart told the Illawarra Mercury. "It did a full 180-degree turn and came back to look at me. That's probably the point I realised I might be in trouble."

Despite the sheer terror of being faced with one of the world's most dangerous predators, the professional engineer recalled the beauty of seeing the creature up close.

"The most amazing memory I have is looking this thing dead in the eye, and wondering if that was the last thing I'm going to see," he said. "I was kind of caught up in the beauty of it."

The shark swam towards Stewart and was seen biting into part of him. Coralie Fleming his diving companion witnessed the incident and thought that the shark had ripped her friend in two. "It opened its massive mouth and as it's closed its mouth it kind of ripped down as it went to swim away," she recalled.

"There was one metre [missing] off Callum's body. I was horrified, then I realised it was just the fin," she added, describing it as an "investigatory bite".

Mitchell Scanlan-Bloor, Fleming's boyfriend managed to capture the encounter on camera before the group of divers scrambled onto some nearby rocks to get out of the water. "We copped a real beating on the rocks but were out of the water within a minute," he said.

Stewart and his group were lucky that the shark decided to opt for a taster. Dr Vic Peddemors, the Department of Primary Industries' head shark researcher said the actions indicated that the great white wanted "a test bite" to see if the diver was worthy of a meal.

"I didn't get the impression it came hurtling at Callum," he said. "If it had, it would have pushed him right out of the water with a shark of that size, and it wouldn't have just been his fin that was missing."

Despite the scary meeting, Stewart stressed that the incident was statistically very unlikely.

"Sharks are intelligent, surprisingly timid, and very selective of their prey. The fact that my two best friends and I are still here, is only testament to this fact," he wrote in a Facebook post. "I am acutely aware of how fortunate I am to have experienced such an interaction and to have come out of it completely unscathed. My thoughts go out to those who were not so lucky."