The head of the Prime Minister's Department, Ian Watt (right).

The head of the Prime Minister's Department, Ian Watt (right). Photo: Andrew Meares

Up to 400 jobs will be cut at the elite Department of Prime Minister and Cabinet and so far there has been a shortfall in the number of workers interested in taking voluntary packages.

Staff have been told between 350 and 400 staff will need to go following Tuesday’s budget.

About 200 staff have expressed interest in voluntary redundancies and another 100 have departed without being backfilled.

This leaves 50 to 100 positions which need to be identified and surrendered between now and the end of June 2015.

Department secretary Ian Watt, who receives a pay rise this July along with other Canberra mandarins, addressed staff about the job losses on Thursday and workers say management was confident this would happen by natural attrition.

The federal budget papers show $534 million would be saved across the forward estimates by rationalising indigenous affairs programs, grant and activities administered by the department.

Another $1.3 million would be saved across four years by ceasing the role of the National Security Legislation Monitor, which scrutinises national security legislation. 

In late March it was reported Prime Minister Tony Abbott's public service department was to cut ''significant'' numbers of jobs.

Senior managers were told the department’s Canberra employees would bear the brunt of the pain while senior executives would also be targeted.

At that time Ian Watt told his staff the department was battling to balance its budget and deliver its programs.

A note to executives was frank about where the axe was expected to fall. ''A large number of staff affected will be Canberra-based,'' it stated.

''Whilst there will be some reductions that will occur in our network, front-line staff are less likely to be affected.''

Staff will have until the end of May to put their hand up for voluntary redundancies.