The Department for Work and Pensions (DWP) has been advised to improve its IT systems to help reduce the cost of administrative errors in the benefit system.
A report by the National Audit Office (NAO) found that due to DWP processing errors, in 2009-10 the department overpaid an estimated 1.1 billion and made underpayments of 500 million.
One major issue cited by department staff was the use of different computer systems to process benefits. In NAO interviews with workers, they claimed the different systems did not communicate well with each other.
In its audit, the NAO said many of the computer systems at the department were "relatively old and standalone." This meant they were difficult to update and data was not readily accessible between the different systems.
"The department continues to work on system fixes' but until it is able to develop a solution to enable integration of its processing systems, the overall impact on administrative errors is likely to be limited," the report read.
Amyas Morse, head of the NAO, said the department clearly wanted to make improvements and cut out mistakes but no real ground had been made.
"The department is clearly committed to reducing the cost of administrative error and it is frustrating that there has been no discernible reduction since 2007," Morse added.
"Progress will depend on developing a better understanding of the costs and benefits of different interventions, so that they can be targeted more effectively and are able to achieve a significant reduction in the cost of administrative error."
The Information Commissioner's Office recently warned the DWP to be careful not to breach data protection laws when using credit reference agency reports in assessing benefit claims.
