National Australia Bank (NAB) has revealed it is placing spoof callers on a ‘Do Not Originate’ list in a bid to help reduce the number of scam calls impersonating NAB numbers.

The bank said it has worked with telecommunications providers to place known numbers on the block list, noting that since implementing its anti-scam updates last December, spoof call numbers have dropped by 50 per cent, leading to a 70 per cent reduction in customer losses to scammers.

NAB said it also added additional protections, including blocking of the bank’s ‘alpha tags’ (the name that appears when someone is calling a smartphone), to reduce scam messages appearing in legitimate bank text message threads.

Spoofing, a type of phishing or voice phishing (also known as ‘vishing’) scam, involves criminals posing as a trusted brand or government agency (via a phone call or SMS) to gain a victim’s confidence and pressure them into either providing their personal details, making a payment, or in some cases to spread malware.

Criminals, NAB notes, now have access to software to mask their phone numbers and appear on a call receiver’s device as a trusted organisation, such as a bank, government agency, or police. The technology is in fact legal in Australia, provided it is used for a lawful purpose, making it widely accessible to nefarious actors.

The bank notes that in one specific case, a NAB customer received a vishing phone call purporting to be a representative from the bank (with the number appearing to match that on NAB’s website) flagging an ‘unusual transaction’ that required the customer’s account to be blocked. The criminal then convinced the victim to transfer money to a new ‘safe’ account – the scammer’s own account.

Despite the bank’s tangible success in blocking many of these spoof calls, NAB’s group investigations and fraud chief, Chris Sheehan, said the wider business sector needs to better collaborate to effectively suppress these scams.

“Scams impersonating NAB and other recognised brands have continued to rise, and it’s clear we need more collaboration across business sectors to stop this occurring,” he said.

“This is not just a problem for banks and telcos. [This] is an issue for every public and private organisation, and we urgently need a more coordinated national response to the issue.”

“By working together in a ‘Team Australia’ response across business sectors, levels of government and the community we can reduce the impact these scams are having,” he said.

Sheehan – a former Australian Federal Police senior executive – confirmed the bank recorded a 38 per cent increase in scam reports from its customers last year.

He added that his fraud call centre receives around 130,000 calls from customers each month, with the centre recently increasing its staff numbers by 140 people to handle these calls more promptly.

“Although we prevented more than $110 [million] in scam losses for our customers last year, too many people are still falling victim and losing large amounts of money.

“That’s why we will continue to work hard to find more ways to protect our customers.”