Ian Watmore began work as head of the e-government unit, part of the Cabinet Office. This replaces the role held by Andrew Pinder, the government's e-envoy.
Watmore has joined from Accenture where he was UK managing director.
He has had previous roles in both the public and private sector in the UK, Ireland, South Africa, New Zealand, the US and Europe.
Watmore is past president of the Management Consultants Association and he remains chairman of the IT industry board of eSkills UK.
Steve Lamey will start work as chief information officer of HM Revenue and Customs, the department that he will help create as a result of the government's planned merger of Customs and Excise and the Inland Revenue.
Lamey has moved from BG Group where he has been chief information officer and vice-president for information management since April 2000.