The UK's spending watchdog has cast doubt on government claims to have made almost £5bn in efficiency savings.
The CBI said civil servants needed to be more professional
Chancellor Gordon Brown wants Whitehall to save £21.5bn by 2008 through job cuts and changes to working practices.
The National Audit Office says some progress has been made but it is concerned about how some of the savings have been calculated.
The government says its programme is "firmly on track" but admits measuring efficiency correctly is "a challenge".
The NAO said that it was cautious about some of the claims being made by ministers on the efficiency targets triggered by the 2004 Gershon Report.
Sir Peter Gershon's spending review suggested spending could be cut by improving procurement practices and use of modern technology, cutting bureaucracy and moving staff away from back-office functions and onto the frontline.
In particular, the NAO was concerned that 68 out of the 300 projects which will deliver the savings did not have baseline figures attached, making it very hard to judge how much was being saved.
It was also concerned that 15% of the overall savings were meant to be delivered by IT projects despite the government's less than perfect record in delivering IT projects on time and on budget.
It also points out that most projects are not taking account of the cost of the efficiency plans themselves when calculating the savings made.
The NAO report comes as a CBI survey suggests nine out of 10 British firms think the government will miss its efficiency target.
'Not very confident'
However, 56% of the CBI's respondents said they were "not at all confident" and 34% "not very confident" the target would be reached.
The CBI sent out surveys to 1,823 companies and received 307 responses.
CBI director of public services Neil Bentley said: "The civil service is poorly equipped to deliver the efficiency programme and needs the injection of new professional skills and a more rigorous and challenging system of performance management.
"Hoping that the expected level of savings will come from the existing set-up is the financial equivalent of rearranging the deckchairs on the Titanic."
Conservative shadow chief secretary to the treasury Theresa Villiers said the NAO report was worrying.
She told BBC Radio 4's Today programme: "I just don't think at the moment that we're seeing genuine improvements to efficiency in the civil service in the way public services are delivered.
"And also, another problem highlighted by the report is we're not getting any guarantees from the department that those savings that they are putting into place aren't impacting on service quality."
Liberal Democrat Treasury spokesman Vince Cable welcomed the report, saying it highlighted the need for ministers to keep on top of the efficiency agenda.
"Although the headlines are always concerned with monetary savings, it is vital to remember that improving service delivery is the key objective," he said.
"Ministers must not look at 2007-08 as an end date for this efficiency drive."