It appears that at least in the case of Westpac Bank Australia, unsolicited scam text messages may be sent to mobile phones. They seem to come from the bank but on closer inspection, you can spot the teltale signs that these messages are not legitimate.
In this case take note of the message and how Westpac has been spelt. Look for spelling errors or weird domain names.
The link points to banking.westpaac.com.au which is different to westpac.com.au (notice the double a in westpac). Clicking the link may result in the installation of malicious software.
The intent of the scam messages may be to install the latest variant of malware that is doing the rounds and is designed to gain access to victim bank accounts.
If you receive any unexpected text messages or emails with links, do not click on any links and report all suspicious activity to your bank.
Please always access your banking services direct through an authorised app or through your bank’s website.