Education ministers were forced to admit this week that their department had spent pound;22 million on management consultants over the past five years.
The figure emerged as the Department for Education and Skills faces pressure from the Treasury to spend more on schools and services.
It wants to ensure that "not one penny more than necessary" is spent on central government, a process that is expected to lead to more than 800 job losses in the DfES alone.
Management consultants can earn between pound;300 and pound;1,000 for a single day's work.
A spokeswoman for the department admitted that it did not know which consultants were used or what they were employed to do. She could only say that consultants had been employed to do "things like" change management, facilitation services and advice on restructuring.
"The DfES only uses consultants to provide necessary skills and expertise that are not available within the department and to provide fresh perspectives, wider experience and a broader perspective on our business drawn from their work with other organisations," she added.
The figures, revealed by Stephen Twigg, education minister, in a Parliamentary answer, are the latest example of controversial spending by the DfES and its predecessor the Department for Education and Employment.
Separate statistics show that the department has spent more than pound;100m on advertising since 1997, working out at an average of pound;17m per year.
This compares to the pound;7.5m which was spent by the then Department for Education and Employment in the Conservatives' final year in office.
David Hart, National Association of Head Teachers general secretary, said:
"These figures show why out of every pound;1 received by the Chancellor only 50p reaches front- line services. The Government spends far too much money at the centre."
Civil service unions are fighting plans to axe jobs in the DfES.
The department is expected to reveal details on the first round of job losses in April.
Tony Conway, DfES group president of the Public and Commercial Services Union, said job cuts would only increase the need for consultants.
"Management consultants cost more than civil servants and are being used to cover work the civil service should do," he said.