The contracts will be open to competition over the coming years with existing contracts being replaced up until 2015, Department of Work and Pensions (DWP) CIO Joe Harley said.
"We are reviewing our plans for our major IT services contracts as our principle existing contracts expire during 2010-11.
"We will be managing a series of competitions to replace existing contracts progressively by 2015."
The first is a contract to provide desktop services across the department from 2010. The department wants the desktop contract to "help drive innovation and further bring down IT costs."
The £3bn figure will also cover contracts for hosting services, voice and data networks, application maintenance and support, data centres, and integration services.
DWP said some existing contracts may be extended on an interim basis. Its contract with EDS, proving data centres, has already been extended.
The announcement came shortly after ex-Logica boss Michael Read was drafted in by the government to review public sector IT projects.
Harley said, "We are committed to ensuring that future IT services continue to be provided in a way which delivers the best service to the citizen and maximum value for the taxpayer."