A nationwide fault left many shoppers unable to make transactions using ANZ/National Bank credit and direct debit cards late this morning.
A spokesman for ANZ said a technical issue briefly disrupted credit card and eftpos transactions at some merchants.
The fault did not affect ATM transactions, he said.
"The issue has been resolved and affected merchants should now be back online.
"We would like to apologise to customers for any inconvenience that this has caused."