Westpac says some of its card services are working again, but it is still experiencing a widespread network outage.
Its website, online banking, card services and contact centre went down before 2pm today.
The bank posted on social media saying it was experiencing a network issue affecting access to its website and Westpac One online banking.
A Westpac spokesperson said tech staff had identified the problem and were working to fix it.
The bank said some credit card services were now working again, so if an Eftpos card was not working, customers should try their credit card instead.
Westpac said it could not say when services would be back to normal.