The 23-year-old was arrested on Tuesday morning at a home in Glen Alpine, on Sydney's southwest fringe.

He was taken to Campbelltown police station, where he is expected to be charged with the murder of Marvin Oraiha.

The 24-year-old was gunned down in his car in Elizabeth Hills on May 23, when he was ambushed shortly after an afternoon meeting with his girlfriend.

Mr Oraiha was found with multiple gunshot wounds and died at the scene despite police and paramedics' attempts to revive him.

He was a low-level associate of the Comancheros bikie gang, sparking police concerns of an escalating war between rival criminal groups.

Two cars were found burning a short time after the murder in the neighbouring suburbs of Green Valley and Bonnyrigg Heights.

Six other people have been charged with playing various alleged roles in the killing, including stealing cars used to commit the crime, and remain before the courts.

Mr Oraiha's death was followed by a string of public shootings, including five in one week during July, as gangs competed for Sydney's lucrative drug trade.

Australian Associated Press