Westpac Bank is investigating a technical glitch that left more than 20,000 customers without $8 million in welfare payments last week.
Westpac spokesman, David Lording said the technical glitch involved computer information for Centrelink and pension payments which caused a delay in deposits to customers' accounts across the country.
Lording said the technical glitch was caused by a file that was too large, which when staff were manipulating it to get it through the system, resulted in the technical difficulties. He said the file was then re-constructed which in turn delayed its processing.
Lording said the problem was had been fixed and would be fully investigated.
He declined to confirm if the technical glitch was a result of human error.