Gladstone Park hardly seems the stuff of nightmares.

This is blue-collar Australia, where six out of 10 locals are Aussie-born and fall into the nation's inverting age pyramid, where the nuclear family dominates, and where most people work as tradies or labourers, or in shops.

The suburb in Melbourne's northwest is struggle town. Families earn maybe A$100 ($125) below the national median income and most are battling to pay the mortgage. Almost half are Catholics, at least nominally.

But last week Yacqub Khayre, a 22-year-old Somali-born Australian citizen from Gladstone Park, who had fallen off the rails in his teens, put his home on a different map.

Rounded up before the winter sun roused Melbourne, he appeared in court accused with four others of planning martyrdom, slaughtering fellow Australians by machine gun in the name of Allah until himself cut down.

The plot as described by police was brutally simple. Influenced by the al-Shabaab organisation waging war to bring Somalia under a Taleban-style fundamentalist regime, Khayre and his colleagues intended to charge into Sydney's Holsworthy army barracks, killing everyone they could.

They would probably have shot their way in successfully. Entry to the base is guarded by unarmed civilian staff and fairly easy to enter, as a reporter and photographer from Sydney's Daily Telegraph demonstrated this week by gaining access and wandering around for 40 minutes before being stopped and arrested.

How far they would have got is less certain. Holsworthy is a front-line base, home to an SAS counter-terrorism unit and paratroopers and commandos attached to the army's special forces command.

The allegations against Khayre are far from proved, and other accusations of violent Islamic extremism have failed in Australian courts.

But the skeleton of the case outlined by police after the massive pre-dawn swoop across Melbourne's north reveals the sum of Australian fears: terrorism born spontaneously in the nation's suburbs.

If the prosecution proves its case, Khayre and his four co-accused will be textbook examples of home-grown terrorism, young men isolated on the fringes of migrant struggle town and seduced by the global vision of radical jihadist ideology.

Khayre's story has been unveiled to the nation by police, friends and family. His family came to Australia in 1991 after Somalia disintegrated into the civil war depicted graphically in the movie Black Hawk Down, sponsored by his uncle, Ibrahim Khayre.

Jacqub was only 3 when he arrived with his four siblings. Most of his childhood was unremarkable: by all accounts a happy, disciplined boy who did well at school.

But at age 12 life soured. His grandfather, a pivotal influence in his life, died, and Khayre began hanging with friends his family considered bad influences.