The lawyer's son told Herald it was a highly sophisticated scam.
"They sounded like a normal bank, nothing to suggest they were scammers. He actually said to them multiple times 'Are you scamming me?' and they were very calm and patient, they weren't aggressive or anything."
The man's son also claimed that ANZ's actual fraud department took too long to respond, which added to his father's confusion.
"[My dad] called the fraud department after he realised he might be being scammed. He was on hold for half an hour, possibly more then it went to answerphone and asked him to leave a message. Then the scammers rang pretending to be from the fraud department which made it very cloudy to tell who was actually calling you."
An ANZ spokeswoman said the bank couldn't comment specifically on the man's case without a privacy waiver.
"We understand when customers get caught in these situations it can be very stressful and we'd like to make sure the customer is getting the support they need," she said.
She said the bank's customers are increasingly being targeted by scammers and that the man's case is a reminder for people all need to be careful with private and financial information.
The lawyer's story matches up with that of children's author Malcolm Clarke who was also called by scammers on what appeared to be a legitimate 0800 number, pretending to be from Kiwibank's fraud department.
Clarke issued a social media warning to others after almost falling for the scam.
The tricksters then asked for Clarke's access code, secure key code and full security phrase and told him they would lock and freeze all his accounts if he didn't provide the information.
Clarke also described the scammers as having a calm and collected demeanour and said that the sophistication of the scam had him "pretty much convinced" that it was a legitimate operation.
As this type of scam continues to impact more Kiwis CERT NZ Acting Manager of Incident Response Jordan Heersping is warning more people to stay vigilant of the convincing scammers
"We have seen an increase in scammers imitating ('spoofing') banks' phone numbers to use in phishing scams. The attackers are convincing because they have done their research and can duplicate what a bank call centre will say. They also use social engineering tactics like urgency, fear and opportunity to engage people and, even if you are aware of this, it could catch you out when you're busy, tired, stressed or focused on other things."
Heersping says if you are caught out by the scam best practice is to report the issue to your bank and CERT NZ, and if any money is taken the police as well. He says if any password information has been given out you should change that password anywhere it is used. He recommends using long and unique passwords that differ for all sites you use.
