Sydney  - Sydney police on Monday bolstered a squad dedicated to breaking up motorcycle gangs after a Hells Angels member was bludgeoned to death in front of horrified passengers at Sydney airport when rival gangs clashed at a check-in counter.

"This is a new low in the activities of these criminal gangs," New South Wales state Premier Nathan Rees said of Sunday's killing. "Where once they kept these things between themselves, this has now overlapped into the public domain."

Rees said the state's Gang Squad would more than double in size to 125 detectives and that new laws could be enacted to tackle criminal gangs.

Four men have been arrested over the death of the 28-year-old at the domestic terminal. He suffered a fractured skull when hit with metal post used to rope off the check-in area.

Police won't confirm a report that the dead man was Anthony Zervas, the brother of a Hells Angels member who had recently been released from jail.

"It looked like two people fighting at first, and then all of a sudden a whole rush of guys came through the crowd, picked up the poles and just started smacking this guy in the head with the poles," witness Phil Crew told national broadcaster ABC.

There have been tit-for-tat clashes between rival gangs that have included premises being firebombed and gang members being shot in the legs. Police suspect the gang warfare is over control of the trade in drugs.

Former New South Wales deputy police commissioner Clive Small said that this was the first fatality of the current round of turf wars but that last time, in the four years to 2002, 20 gang members had died.

"There is an attitude in motorcycle outlaw gangs that they don't care about the community, they don't care about innocent people, and they think they are the boss and we will do what we want," Small said.

South Australian state Premier Mike Rann said other Australian jurisdictions should follow Adelaide and simply proscribe outlaw motorcycle gangs so that anyone proclaiming themselves a member could be arrested and charge for being a member of a criminal gang.

"We're treating bikie gangs as you would treat terrorists," Rann said. "These are basically terrorists within." (dpa)