Former ambassador new department head

The federal government has continued its overhaul of senior public servant posts with the appointment of a former ambassador as the head of the Department of Prime Minister and Cabinet.

Former Australian ambassador to the United States Michael Thawley will take over the post from December 1.

He replaces Ian Watt, who is the fifth department head to leave the government since the September 2013 election.

Mr Thawley was based in Washington from 2000 to 2005, during which time he drove negotiations on the Australia-US free trade agreement.

He is also a former senior adviser on international relations to John Howard.

Prime Minister Tony Abbott thanked Dr Watt for his years of dedication to the public service.

Dr Watt has been secretary of the departments of communications, finance, defence as well as PMC.

"He has served successive governments with distinction and his contribution to public administration in Australia has been wide-ranging," Mr Abbott said.