Sydney - Australian police promised more arrests Wednesday as a squad dedicated to breaking up motorcycle gangs rolled through major cities picking up suspects in a show of force.

The crackdown follows Sunday's outrage when a Hells Angels member was bludgeoned to death in front of horrified passengers at Sydney airport.

Fears of outright war between rival gangs were stoked by a double murder in Canberra on Tuesday. But police warned against immediately linking the killings to gang rivalry.

"There is nothing to suggest that this is in any way related to some sort of broader bikie gang-related criminal activity or some sort of turf war between bikie gangs," Canberra Police Minister Simon Corbell said.

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

Hours after the Canberra shooting, Sydney police picked up 27-year-old Mahmoud Dib, a senior member of the Bandidos gang, and charged him with six firearms offences. A loaded gun was found in his car and police are examining it to see if it was used in any of the 11 drive-by shootings of the past six days.

In the shootings, unidentified people have shot indiscriminately into houses, including Dib's, in what police believe are tit-for-tat attacks. Rival gangs have firebombed each other's headquarters and gang members have been shot in the legs.

Police suspect the gang warfare is over control of the drug trade.

Former New South Wales deputy police commissioner Clive Small said that in the four years to 2002, 20 gang members had died and that this was the latest round in a turf war.

"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.

Prime Minister Kevin Rudd promised a national response. "This sort of behavior by bikies and others engaged in organized criminal activity is unacceptable in Australia, absolutely unacceptable," Rudd said during a visit to the United States. (dpa)