The Department for Transport and the Department for Communities and Local have become the first to be hosted under the new site.
The new domain will also include public sector agencies and bodies, with the Building Regulations Advisory Committee, Driving Standards Agency and the Planning Inspectorate having already been transitioned to the GOV.UK site.
GOV.UK which went live last month has been designed to host all department sites, generating savings of over £50 million a year.
Cabinet Office Minister Francis Maude said that the new site will offer improved services: “Information will be easier to access and more open, and we will save the taxpayer millions of pounds in the process".