A spending watchdog has warned that the rush to slash billions from Whitehall spending could result in short-term service cuts instead of long-term efficiencies.
The National Audit Office (NAO) said it remained unclear what share of a £6.2 billion reduction in budgets this year would be met by simply turning off the tap.
"Because of the short time scale, there is a risk that much of the cost reduction achieved by departments in 2010/11 will result from policy decisions to withdraw funding and reduce budgets or other short-term measures, rather than structured and sustainable cost reduction," it concluded.
The verdict was delivered in a report on the senior Efficiency and Reform Group set up at the centre of Government to co-ordinate money-saving efforts as part of the tight squeeze on state spending imposed by Chancellor George Osborne to tackle the UK's deficit.
Cabinet Office Minister Francis Maude has described its task as to "take the cost out of the centre of government so we could protect the front line".
The NAO said it was too early to judge the success of the group - which it likened to the replication of a traditional corporate headquarters set-up at the centre of Government - but it raised a number of potential hazards the body faced as it took on responsibility for renegotiating contracts with major suppliers, implementing a centralised procurement process, reviewing major government projects and looking at property use.
The costs of cancelling projects, money saved from axeing schemes being transferred to others or entire new ones needing to be set up down the line, were among "potential risks".
Some key initiatives "may have been delayed or harmed" by massive cuts in the use of consultants, the NAO said, and an external recruitment freeze raises the risk that "key services are not maintained, that work contracted to the private sector is more expensive, and that short-term financial gains are offset by future costs".
Whitehall departments might also find ways around moratoria on spending in certain areas but shifting costs elsewhere or "repackaging spending to keep under threshold", it said.
Amyas Morse, head of the National Audit Office, said: "We welcome the Efficiency and Reform Group's twin priorities of improving the efficiency of central government and reforming public service provision. However, the proof of the pudding is in the eating and we look forward to evaluating how these initiatives perform in practice."