Expotel joins BSI on the Buying Solutions travel management solutions framework, which will go live from September.
Further agencies will be announced on the framework as contracts are finalised, said a Buying Solutions spokesman.
Expotel has been appointed to six separate lots on the framework and will provide air, ferry, rail, and serviced accommodation in addition to its existing responsibilities for hotel accommodation and conference and event bookings.
Expotel chief executive Ian Burnley said: "We continue to work closely with many of the key departments across central and local government, as well as other public sector bodies. Expotel has delivered significant savings to its public sector clients for many years in the hotel and conference markets and we are working closely with all these key stakeholders to meet the challenges and tough targets being set by the new government."
Defra and the Department for Work and Pensions are among public sector clients Expotel has worked with.