The 42-year-old, suspected of being the "organiser" of the murder, was allegedly attempting to leave the country on Friday morning, just 24 hours after fellow Rebels gang member Robert John Stewart McCloskey was arrested and charged over the 2013 slaying.

Mr Salafia, 38, was shot in the head and chest after answering a knock at the door of his Kings Point residence late on a Sunday night more than four years ago.

The one-time Rebels bikie gang member died where he fell as his young family remained inside.

Strike Force Hobler detectives swooped on McCloskey during a dawn raid on his home at Surfside, near Batemans Bay, on Thursday morning.

Read more: Unsolved murders of the Illawarra and South Coast

It is alleged McCloskey, who was formally denied bail during a brief court appearance, fired the fatal bullets.

The second man was arrested about 8.30am after he had checked in at Sydney Airport for an international flight.

He has been taken back to Mascot police station and is expected to be charged with murder.

Shortly after the arrest, investigators executed a search warrant at a home at Burrill Lake, where they seized items.

Senior homicide squad investigator, Detective Chief Inspector Mark Henney, said police would allege the two charged men were "the shooter" and "the organiser".

He said more arrests were expected.

"There are a number of other people who were involved who were present at the time of the murder, or assisted before and after the murder," Detective Chief Inspector Henney said.

"This includes people who assisted in disposing of the vehicle used in the murder."

He said the investigation would now focus on other people believed to be connected to the murder.

"We know there are people out there in the community who have information about this murder," he said.

"We continue to appeal to those people who may have been reluctant to come forward, to speak to police and provide information on this murder."

Mr Salafia had just finished putting his young daughters to bed after a night spent at the movies when the doorbell rang.

Mr Salafia's death was a tragedy for his loved ones. As well as his two daughters, he was married, and also had a son with his ex-wife.

Just over a week earlier he had survived a fatal crash at Bargo, in which an elderly man was killed.

His ex-wife, Carly Stewart, told Fairfax Media in February that Mr Salafia had briefly been a member of the Rebels outlaw motorcycle gang in the early 2000s.

Ms Stewart said his membership only lasted six months after friends convinced him to join.