Caller: NAB

This is the NAB Card Fraud hotline.
IF you've experienced card fraud, these are good folk to engage with.

Yeah, I can confirm this is the NAB Fraud Prevention line. They tried calling me as they'd detected suspicious charges to my credit card and my credit card had been locked down simultaneously. When I enquired about this via my online banking account I was also given this number to call.

this number is listed as suspicious but i believe its the nab fraud prevention hotline. i didnt recieve a call from it but recieved an sms saying to call this number.

This is National Australia Bank fraud prevention.  I have been helped by them more than once when there has been suspicious activity on my credit card and can confirm they're legit.  Also, if you don't call them back they're likely to put a hold on your cards and you won't be able to access your cash.