A major IT issue has made Permanent TSB customers unable to receive payments or use the mobile application.
The bank has said it is having an issue with SEPA payments due to a problem connected to a "third-party payments provider".
It had been expected the issue would be resolved by mid-morning, however problems are still arising.
Irish Independent Personal Finance Editor Charlie Weston said this outage could not have come at a worse time.
"It's almost every week now that some bank has an issue, an IT outage of some kind, it's a regular occurrence – but the timing of this one is pretty bad, because it comes on a Friday,” he said.
"People need money to do their grocery shopping – also, a hell of a lot of people are looking to make a sale for Black Friday.
"I mean, it's one of the biggest shopping days in the last while."
Over the last few years, Black Friday has "become huge in this country", Mr Weston said.
Some users have now received payments, but the mobile app appears to still be down.
File photo shows the Permanent TSB logo at its 2014 AGM in Dublin | Image: Mark Stedman/RollingNews.ie
