An error at Clydesdale and Yorkshire Banks has resulted in customers not receiving payments into their accounts.
Many customers of the group, which also includes Virgin Money, took to Twitter to make their frustrations clear at wages and other funds not appearing.
Fears were expressed relating to bills that were due to go out as well as the difficulty contacting the banks over the phone.
The banks' initial response was for customers to contact their employers to chase their missing wages before it became clear this was a wider issue.
The bank has in turn apologised and assured customers that it is conducting a full investigation and that customers would not be "negatively impacted financially", pledging to make good on any charges incurred as a result.
A similar incident occurred at TSB in late November where a processing error prevented wages and other payments appearing in customers' accounts, which was resolved later that day.
This is also the second error to afflict a major UK bank in the three-day-old new year after Lloyds Banking Group was hit by an online banking outage on January 1st.
Customers of Lloyds, Halifax and Bank of Scotland were unable to access their internet banking for around nine hours on New Year's Day.
The problem surfaced at around 3am with customers also taking to social media to make frustrations clear about being unable to make transfers and check accounts.