Scammer tries to rip-off Westpac customer. Listen to the audio recording

The politely spoken, English-accented man on the phone identifies himself as Martin Moore from the bank's fraud prevention team and tells the Westpac customer that her credit card had been used for a transaction in Mexico.

He has the customer's credit card number and with a series of clever and plausible questions and responses he attempts to make an online purchase for himself by getting a transaction approval code from her.

The customer eventually becomes wary and says she will have to contact her personal banker and call the scammer back. The attempted scam failed after Westpac detected the suspicious transaction before any funds were sent.

Listen to the impersonation scam call below.

The call demonstrates some of the danger signs customers should watch out for and the bank is warning customers to be extra careful after a recent spike in activity.

New Westpac data has found reported scams increased 33 per cent in July from the year prior as scammers become increasingly sophisticated and difficult to detect.

Impersonation scams are among the most common scams currently targeting customers.

In a bid to combat these scams, Westpac has worked with Optus to become the first private Australian business to block calls from scammers impersonating the bank.

More than 94,000 Westpac phone numbers have now been added to a 'Do Not Originate' list, which will prevent scammers from impersonating Westpac numbers. The list is also shared with other carriers to extend the protection across different networks.

"We've seen a significant increase in cases where scammers are using software to mask their phone number with the number of a known business. This is a commonly employed tactic in impersonation scams known as 'call spoofing'," said Westpac head of fraud, Ben Young.

"These scams are incredibly challenging to detect because from the customer's perspective, they appear to be getting a call from say Westpac, when in fact, it's a scammer posing as a member of our fraud team calling from a completely different number.

"The scammer will then use personal information they've fraudulently obtained, like quoting the customer's name or last few digits of their credit card, to convince them the call is genuine."

Mr Young said it was not only banks scammers are impersonating, but also telco or energy providers, online retailers, government organisations, or even pretending to be family members.

To combat these scams, the bank is working with telco partners to apply blocks that now stop scammers from being able to use call spoofing software and impersonate calls using Westpac's number.

Mr Young urged people to remain cautious of any unexpected phone calls, text messages or emails from a known business and always consider what they're asking you to do. If ever in doubt, hang up and call back on a publicly listed number to ensure the call is genuine."

Westpac is taking additional steps to support customers over the coming months. These include increasing scam specialists by 50 per cent and launching new digital chat capabilities to enable branch staff to connect directly with Westpac's scam team.

"We want customers to know that support is available if they need it," Mr Young said. "If you think you may have been scammed, it's important you contact your bank immediately. The sooner you act, the better chance we have at reducing the impact of that scam."

More information about the latest scams and how to avoid them is available at westpac.com.au/scams. To report a scam or to seek assistance, customers can call 132-032 or via the Westpac app.

Read about other scams at www.scamwatch.gov.au