Union leaders today attacked plans by the Ministry of Defence to cut a further 7,000 civilian posts as "shameful".
The Public and Commercial Services union (PCS) said it was "totally unreasonable" for the MoD to be cutting so many posts when efforts were still being made to reduce a previously announced cull of 25,000 jobs.
Officials said they had met Defence Secretary Liam Fox several times in recent months after the Government's strategic defence and security review proposed axing 25,000 civilian and 17,000 military jobs.
Staff are expected to be sent a letter today from the MoD saying that further job reductions will have to be made.
PCS general secretary Mark Serwotka said cutting so many civilian and military jobs could put lives at risk, adding: "This is a shameful way to treat anybody, far less the people who serve on the front line, and those who support them.
"Since the defence review announcement in October, PCS has been thwarted at every turn in our attempts to find out where these cuts will be made and what impact it will have on the front line.
"How can the MoD announce more job cuts when they have no idea how they will run the department just now? PCS has been working on a coherent programme for defence that identifies and reduces waste, frees up service personnel to serve in the front line by civilianising non-essential military posts and eliminating unnecessary external expenditure.
"According the MoD's own records, they spend approximately £6 billion per annum on external expenditure such as consultants."
An MoD spokesman said: "The Government has tackled the £38 billion black hole in the MoD's finances, delivering substantial savings through difficult but necessary decisions.
"The aim of these cost savings is to ensure that the maximum funding is available for the front line.
"We hope to achieve these efficiencies through natural wastage wherever possible with compulsory redundancy programmes serving only as a last resort."
Steve Jary, national officer of the Prospect union, said: "This announcement is a bolt out of the blue and staff will rightly be appalled at how the department has gone about the process. It was not mentioned last week in the House of Commons by Defence Secretary Liam Fox and has not been subject to any consultation at all.
"We are close to a fundamental breakdown of trust with officials. The department keeps announcing significant changes without any consultation, not even advance notification.
"This is in stark contrast to a useful meeting with Liam Fox last week where he agreed that unions will be fully engaged in the defence reform process set out in Lord Levene's recent report - especially in securing the cultural and behavioural changes suggested by Levene.
"This core message seems to have been lost on senior officials who plough forwards on a course that spells disaster for the department. The announcement is about what MoD can afford, not what it needs. The reality is that the destruction of MoD's cadre of specialist staff will mean increased costs for defence, through poorer and more expensive equipment and poses a risk to our armed forces.
"No one knows what the defence budget will be after 2015, MoD does not even know what its civilian requirement will be for next year."