Brazilian professional surfer Ricardo dos Santos has died after being gunned down by a police officer outside his house.

The 24-year-old was attacked on Monday near the city of Florianopolis after he confronted the off-duty policeman and his brother. He was shot three times in the abdomen.

Witness reports suggest he was killed after getting into an argument with the men.

Police officer Luis Brentano, 25, is under arrest on suspicion of murder but has not yet been charged.

He claims he acted in self defence after dos Santos threatened him with a knife and tried to attack him.

However, police investigator Marcelo Arruda told Brazilian news site GL Globo that no weapon had been found at the scene.

Dos Santos was flown to hospital by helicopter but died on Tuesday, despite four operations to save his life.

Surfer magazine paid tribute, calling him a "fearless, world-class tuberider".

The high point of his career was a surprise win at the 2012 Billabong Pro Tahiti Trials, beating an experience field including surf legend Kelly Slater.

The same year he also won the Surfline Wave of the Winter award for riding an "incredibly deep, blue, massive Pipeline tube".

(Sky News)