Mastercard System Update Causes Outage and Declined Payments Across Australia

Card payments have been declined for shoppers around Australia due to a Mastercard system update, the multinational card provider says.

"A scheduled system update caused Mastercard transactions to be declined for a period of time earlier today. The situation has been resolved and all systems are working as normal," Mastercard told the ABC in a statement.

Shoppers across several Australian states reached out to the ABC to report issues with card payments, including using Apple pay, making cash withdrawals and using Mastercard travel cards.

Commbank said the problems were due to a "global Mastercard issue," which had been resolved.

Jackie Wells from Bayside, Victoria, was trying to pay for her shopping at Aldi when two of her cards were declined.

"I tried one card and it was declined, tried another card and it was declined, so we went to another POS station and they were both declined again."

Ms Wells then called her husband to bring a different card, which was also declined.

When the couple wasn't able to withdraw cash with their cards, they decided to leave the shopping cart behind in the shop's cool storage area and go home to pick up cash.

She said she saw others shoppers exiting shops "disgruntled" because they weren't able to pay for their shopping.

By the time she returned to the shops, the payment issue had been resolved.

Downdetector, a website where users are able to report service outages, had more than 1,700 reports of Mastercard issues at 3pm on Saturday.

Those reports were down to 173 two hours later.

The most common issues reported on Downdetector involved funds transfers and mobile banking.