An Australian Hells Angel whose brother was bludgeoned to death at Sydney airport was under guard in hospital on Monday after being shot several times, police and media reports said.
In the latest episode in the country's ongoing biker war, police said the 32-year-old survived after being shot late on Sunday outside his Sydney home and was in a stable condition in hospital.
News reports said the victim was Peter Zervas, whose brother Anthony was beaten to death at Sydney airport on March 22 during a brawl that saw simmering tensions between biker gangs explode into public violence.
The commander of the New South Wales Police Gangs Squad, superintendent Mal Lanyon, said there was little doubt the gunman was from a biker gang.
"I think it's probably realistic that we will be looking at other motorcycle gangs," he told ABC radio.
Lanyon said he was concerned at reports biker gangs were stockpiling weapons and bringing members of overseas chapters to Australia as reinforcements.
But he said police were on top of the situation after an extra 75 officers were drafted into his squad last week, almost doubling its strength.
"The police are in control of these matters, the police are certainly taking them seriously," he said.
"Obviously I'm not about to tell you these matters will stop today but certainly we treat them seriously."
Authorities in New South Wales state have fast-tracked laws that allow police to ban nominated biker groups, with the threat of up to five years in jail if members continue to associate with one another.
The laws have come under fire from civil liberties groups but state Premier Nathan Rees said the latest shooting showed they were urgently needed.
"This underlines the need for the new laws that we're going to introduce that will proscribe gangs and make it an offence to associate with a gang," Rees said.
"These are strong new laws, but they are in equal measure to the brazenness with which these criminal gangs are carrying out their activity."
Experts say the violence stems from turf wars over drug distribution, particularly methamphetamine or "ice".
The last time Australia's bikers battled in public was 25 years ago, when six gang members and a teenage girl died in a shootout between the Bandidos and Comancheros in the car park of a Sydney pub.