THESE haphazardly built brick walls are much more than an eyesore in a quiet suburban street - they have struck fear into neighbours and the local council.
Built by bikie gang associates who live in the Greystanes house, they block out the main windows of the home in a crude defence against drive-by shootings.
They are reinforced by an extra layer of security in the form of a group of heavily muscled men who regularly patrol the front yard.
Nearby residents have been terrified the fortifications, erected a few weeks ago, signal their street is about to become a battlefield in the gangland feuds gripping west and south-west Sydney.
Sydneysiders often awake to morning radio reports of yet another drive-by. Last week a man was shot dead in his drive-way in Glen Alpine.
Although the walls on the Greystanes house are illegal, Holroyd Council has been warned by police not to go near the house, or issue an infringement notice, without a police escort.
Residents, who did not want to be identified, said they were terrified to be living on the same street as the group and were frightened that they would find themselves caught in the crossfire.
One resident, who said he was afraid of his neighbours, said the walls went up after the shooting of one of the group's associates.
"I heard this guy's brother got shot and then a week later the structure went up," the resident said.
Another local said she had heard rumours that the group involved were "related to the Ibrahims and with a gang called Notorious".
"They don't talk to us at all, I don't think anyone really knows them," the resident said.
The Sunday Telegraph has learned that Mouhamed Tajjour and Sleiman Tajjour, who are cousins of the Ibrahim clan, are among past occupants of the house.
But the property also acts as a base for associates of the bike gang Notorious.
The Tajjour brothers, alongside Michael Ibrahim, were convicted of manslaughter over the 2006 stabbing death of Robin Nassour, the brother of SBS TV Fat Pizza star George Nassour.
Although both Tajjour brothers have been released from their stint in jail for that crime, Strike Force Raptor, established to target bikie gangs, recently re-arrested Sleiman Tajjour for breaching his parole conditions, landing him back behind bars.
Mouhamed Tajjour is on parole and is understood to reside at the Greystanes house.
Police have confirmed they believe the houses' occupants are linked to Notorious and their intelligence indicates the walls were built to stop bullets.
It is also understood the house has come under the notice of the State Crime Command, although a spokeswoman would not confirm it was investigating the group.
The gang moved in to the area about one year ago, but became so worried about being targets of a shooting they built the brick walls eight weeks ago.