Cabinet ministers, senior bureaucrats and Coalition backbenchers are outraged at the appointment of a former Greens candidate to a senior position in the Department of Prime Minister and Cabinet on the eve of the federal election.

UnitingCare Australia national candidate, Lin Hatfield Dodds, won the job as deputy secretary for social policy in the department.

Ms Hatfield Dodds was a Senate candidate for the Greens in the Australian Capital Territory in 2010 but was defeated by the long-serving Liberal senator Gary Humphries.

The ABC has been told the appointment was confirmed by the departmental head, Dr Martin Parkinson, just before the Government entered its election cycle caretaker mode and without reference to the Prime Minister.

A spokesman for the department told the ABC: "Ms Hatfield Dodds was appointed following a merit selection process conducted in the usual manner and consistent with the Public Service Act."

The appointment has revived suspicions in the conservative ranks about Dr Parkinson, who was dumped as Treasury secretary in the months after Tony Abbott was elected in 2013.

Alison Larkins is currently the deputy secretary [social policy], though it is listed as an acting arrangement on the department's website.

Ms Hatfield Dodds is also still listed as the chair of the Australia Institute, a prominent left-wing think tank.