Update - 5.35pm: The outage of credit card machines at Penneys has been fixed.
Primark have released a statement saying: “Primark can confirm that there was an issue with our partner, payments services provider Elavon, which caused a temporary outage with card machines in Penneys stores.
"This has now been fully resolved."
4.26pm: Penneys working to fix credit card machines
Penneys say they are working to resolve an outage of its credit card machines.
It is not clear if the issue is affecting all Irish stores.
A spokesperson says it is unclear if it is an internal or external problem.
The issue was reported earlier at the retailer's head office.