Ministry of Defence workers are to launch a campaign for fair treatment this week in the face of looming job losses following the strategic defence and security review (SDSR).
Representatives from the Prospect, GMB, PCS and Unite unions will deliver a proposal for a "civilian covenant" to Ursula Brennan on Monday, as she starts her first day as the MoD's permanent secretary.
The unions want the agreement to be similar to the military covenant, the informal understanding of loyalty between the nation and the armed forces.
Prime Minister David Cameron announced in the SDSR that the MoD's civilian workforce will be cut from 85,000 to 60,000 by 2015.
Prospect national secretary Steve Jary said: "MoD civil servants face numerous pressures created by the intensity of military operations and pressures on the defence budget and on civilian numbers.
"They have been reviewed and restructured to the point of exhaustion and the strategic defence and security review and further Treasury-inspired cuts now confront them with a pay freeze, attacks on their terms and conditions and the loss of one in three jobs, coupled with the spectre of compulsory redundancies."
Mr Jary said the civilian covenant would set out the "higher level principles" of fair treatment and help limit the impact of the cuts on morale.