Government departments which have spent millions in laying off staff are responsible for nearly $1 billion in consultants' fees.
Figures provided by the Labour Party showed ten agencies have spent $910.5 million on contractors since 2008 while also spending $114.1 million on redundancies.
The restructuring of the Inland Revenue Department (IRD) had seen departing staff collect $31.3 million in redundancy payments before contractors were hired at a cost of $125 million.
Labour's State Services spokesman Chris Hipkins said the figures made a mockery of National's claim that it was moving resources from the back office to the frontline.
"The public service has already lost a huge amount of valuable expertise and experience and is simply plugging the gap by hiring consultants.