It also finds that a tiny number of communities are shouldering most of the disadvantage burden in the state, in a pattern that is repeated in other states and territories.

The Dropping off the Edge report, published by Catholic Social Services and Jesuit Social Services, tracked 621 NSW postcodes across 21 indicators of disadvantage, including internet access, incomes, education level, literacy and numeracy, long-term unemployment, unskilled workers, juvenile offending and criminal convictions.

It then looked at the number of times a postcode occupied a top 5 per cent spot in terms of the indicators, finding that just 6 per cent of postcodes occupied 49.5 per cent of the top spots.

This compares to 70 per cent of postcodes that did not make any of the top rankings.

Brewarrina, Claymore, Lightning Ridge, Walgett, Wilcannia and Windale were ranked as the most disadvantaged by the report, written by Sydney University professor Tony Vinsonand associate professor Margot Rawsthorne. Bourke, Villawood and Kempsey were not far behind.

In a finding that has the community sector calling for more government action to tackle disadvantage, more than half of the 40 most disadvantaged postcodes were in the same category in a similar 2007 study, with many also repeating the result in 2004 and 1999 studies.

"What this report tells us is that disadvantage is entrenched in a small number of Australian communities, most of which have remained similarly disadvantaged for more than a decade," Jesuit Social Services chief executive Julie Edwards said.

Natasha Mamic, 31, has lived in the Mount Druitt area of Sydney — rated as disadvantaged in the 2015 and 2007 reports — for most of her life.

The single mother of a 10-year-old and a five-year old, who helps at a friend's cafe and volunteers at a local play group, says job opportunities in the area are hard to come by.

She says people also tend to react badly "when you tell them where you're from".

"It's hard with discrimination, and stories like [SBS program] Struggle Street coming out, don't make it easier."

Services are also difficult to access. When Ms Mamic needed access to a refuge due to domestic violence, she had to go to a different part of the city.

She has also been unable to get the internet installed in her home, making it impossible to do an online course she wants to study.

Ms Edwards said that "people can't overcome structural disadvantage when all the odds are stacked against them".

"While our social support structures work for many Australians, this report shows clearly there are a small but significant number of communities we have failed and a new structure – a new approach – is needed."

The report calls for federal and state governments to set up units to co-ordinate community programs by government and non-government organisations.

NSW postcodes in the top band for disadvantage, listed alphabetically:

Brewarrina

Claymore

Lightning Ridge

Walgett

Wilcannia

Windale

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