SYDNEY, May 24 -- Two Australian men were left bloodied and injured on Thursday after a giant Marlin jumped into their boat and began thrashing about with its potentially deadly-sharp bill.

The men, brothers aged 46 and 48, were driving their boat on Australia's mid-east coast when they accidentally hit the Marlin, causing it to breach the water and land in their boat.

Marlins are a type of swordfish, characterised by a long, sharp "bill" which protrudes up to a metre long in front of their mouth.

"The fish, which they estimated weighed between 80 and 100 kilograms, crashed into the brothers on board the vessel, which had been travelling at 21 knots or 40km/h," New South Wales Police said in a statement.

As the animal thrashed around the five meter vessel, the younger brother received a large gash on his lower right arm.

"The Marlin's sharp snout sliced the younger brother's lower right arm, causing an open fracture," police said.

As the creature continued to writhe, the older brother also sustained an injury in the form of a deep cut to his right shoulder.

After that the fish managed to wriggle off the vessel and back into the water, leaving the third man unharmed.

Paramedics attended the scene, transporting the younger brother to a hospital via helicopter while the older brother with less serious injuries was driven by road to the same hospital.

Both men were said to be in a stable condition.