IT projects have contributed around £11bn to a total overspend of £19bn on government projects, according to a report by the Taxpayers Alliance.
The project with the biggest overspend is the National Programme for IT in the NHS, which is £10.4bn or 450% over budget, the report said.
This was followed by a £342m project overrun for Libra, a project to links magistrates court systems, and £279m for Nomis, which aims to track offenders through the criminal justice system.
The Department for Work and Pensions' central payment system was £88m over budget, its customer information system was £48m over, and the Armed Forces Joint Personnel System (JPA) ran over budget by £24m.
Too many projects are coming in late and over budget, and this failure is costing the taxpayer billions, endangering essential services, said John O'Connell, policy analyst at the TaxPayers Alliance.
"Sadly, it seems like the public sector's record is getting worse, not better, over time," he said.
Realigning priorities and increasing management stability can help to correct the failings of the public sector in capital project procurement, said the report.
Fundamental to the success of a project is consistent leadership, strong governance and close monitoring by a central project management team, it said.