An Australian fisherman caught a far bigger fish than he hoped for when a 2.7-metre (nine-foot) great white shark leapt into his boat, knocking him off his feet.

Terry Selwood, 73, was left with a badly bruised and bleeding right arm where the airborne shark struck him with a pectoral fin as it landed on him on the deck of the 4.5m (15ft) power boat on Saturday off Evans Head, 450 miles north of Sydney.

Mr Selwood sprung up on the gunnel at the bow of the boat to avoid the thrashing shark and steadied himself by clinging to the tubular metal frame of the sun shelter, known as a bimini.

"I didn't give it a chance to look me in the eyes. I wanted to get up and get on top of the gunnel because it was thrashing around madly," Mr Selwood told Australian Broadcasting Corp.

The shark was thrashing inside the boat, taking up the entire deck area, there was no way you'd put a foot in there.

"Flash Gordon wouldn't have caught me," he said, referring to the athletic science fiction comic book hero of the 1930s.

Mr Selwood used a hand-held radio to call the Evans Head coast guard and stayed on the gunnel until a rescue boat arrived.

Coast guard skipper Bill Bates said he misread the danger when Mr Selwood reported his predicament.

"He said, 'I'm injured, I've broken my arm, I've got lacerations and there's a shark in my boat'," Mr Bates said.

"Often a fisherman will bring a small shark on board, maybe two or three feet, and they're still ferocious.

"That's what I was expecting, but I was totally wrong," he added.

The coast guard crew rescued Mr Selwood, but left the shark alone.

The shark was estimated to weigh 200kg (440lb).

"The shark was thrashing inside the boat, taking up the entire deck area, there was no way you'd put a foot in there," Mr Bates said.

The coast guard took Mr Selwood to paramedics at Evans Head, where his badly swollen arm was cleared of any fracture.

The coast guard later towed Mr Selwood's boat with the shark into Evans Head just before nightfall.

"We think it was already dead at that stage, but no one was game to put their finger in to find out," Mr Bates said.

Why the shark flung itself over the motor and into the anchored boat is a mystery.

Mr Selwood said he was sitting on a cooler, known generically in Australia by the popular brand name Esky, with two hand lines off the port and starboard sides of the boat when he saw one of the lines move as if a fish was hooked.

"I hopped up off the Esky, I touched the hand line and I just caught a blur coming in the corner of me eye," Mr Selwood said.

"Just out of instinct, I threw my right arm up and this thing hit me in the forearm and spun me around and knocked me off me feet.

"This thing was beside me and I looked over and thought, 'Oh, a bloody shark'. So I just climbed, he was doing a mad dance around, he was thrashing everywhere," he added.

Mr Selwood said he will have to replace destroyed equipment, including buckets and coolers, before returning to the fishing spot he has visited for more than 50 years.

"He didn't do anything structural to my boat, it just smashed anything that was in his road.

"You can understand, he was a wild creature out of his comfort zone," Mr Selwood said.