Mastercard card payments are being declined for Australian clients due to a "global Mastercard issue", Commbank says.Shoppers across several Australian states have reached out to the ABC to report issues with making card payments.Issues with Apple payments, cash withdrawals and Mastercard travel cards were also reported.Downdetector, a website where users are able to report service outages, had more than 1,700 reports of Mastercard issues at 3pm on Saturday.The most common issues reported on Downdetector involved funds transfers and mobile banking."If customers experience a decline, please insert your card and select 'savings' to make payments via eftpos," CommBank said in a statement on its website."All other CommBank services, including ATMs, remain available."The ABC has contacted Mastercard for comment.