The federal government's biggest department is spending $30 million hiring casual and short-term labour while shedding more than 2400 of its permanent staff.

The Department of Human Services is facing a $66 million loss this financial year blamed on a burgeoning workload, natural disasters and a delayed redundancy program which was supposed to bring its wages bill down.

Kathryn Campbell, Secretary of the Department of Human Services.

The department, which provides frontline services Centrelink, Medicare and the Child Support Agency, will see 1340 jobs cut in 2013-14, according to the budget papers, after shedding 1078 jobs in the last six months of 2012.

But according to secretary Kathryn Campbell, the budget gave Human Services $30 million for a "flexible workforce", most of whom will be put to work to improve its customer services.