The humble suburban letterbox has emerged as the new crime-fighting battleground.
NSW Police say increasingly sophisticated syndicates are using networks of street-level "boxers" and ex-bankers with inside knowledge to steal personal data on a massive scale.
The head of the State Crime Command's Fraud and Cybercrime Squad, Arthur Katsogiannis, on Wednesday warned that criminals were swiping electricity bills and bank statements, and mining social media to build complex profiles of unsuspecting victims.
He said mail theft, and the subsequent identity fraud, was overtaking break-and-enter robberies.
"The 21st century bank robber no longer carries a shotgun or wears a balaclava - they're armed with a laptop and a smartphone, and they hide behind the anonymity of the internet," Detective Superintendent Katsogiannis said in Sydney on Wednesday.
"In the past, for traditional crimes, you'd locate jewellery, mobile phones and televisions.
"They're now locating loads and loads, hundreds of pieces of documents and information, credit card information, personal information about yourselves and the community."
He said personal information was being sold overseas to fund criminal activities, including terrorism.
Fraud expert Detective Inspector Matt Craft said mail thieves tended to work along rail corridors, targeting large apartment buildings with many dozens of letterboxes in one place.
The better organised operators came armed with master keys and props to help them blend in, he said, while other "boxers" were former bank employees or financial institution insiders who were servicing drug habits.
"The ultimate aim of these syndicates is to complete an identity takeover," Det Insp Craft said.
"Once they've done that, the sky's the limit. They can go and apply for credit cards in your name, get personal loans, they can do a range of things, because essentially they're purporting to be you."
Chief Superintendent Brad Shepherd, the NSW Police Force Corporate Sponsor for Crime Prevention, warned residents to use padlocks on their letterboxes and to clear mail regularly.
Homeowners should re-direct letters or have their friends collect their mail when on holidays.
Chief Supt Shepherd also urged strata managers to consider putting letterboxes in tenant-only areas and installing CCTV systems to catch and deter mail thieves.
© AAP 2016