The Central Bank has been tasked with getting to the bottom of Bank of Ireland's technical error.
Finance Minister Michael McGrath says he wants a full account of the incident and how to prevent it from happening again.
The bank's online services crashed last night, later leading to malfunction which saw customers able to withdraw funds over their normal limit.
Susanne Rogers from Social Justice Ireland says that may have serious consequences for some customers, with Bank of Ireland saying all withdrawals will applied to their accounts today: