Union chiefs claim 81 civil service jobs have been lost on the Fylde over the past three months.
And they say they are still waiting to hear whether new jobs will be allocated to the area as part of changes to the benefits system.
The PCS civil service union says 61 jobs have been lost at Norcross, and 22 at Warbreck, while two jobs have been created at Peel Park.
Branch secretary Duncan Griffiths said: “We are concerned about the job losses.
“These figures show that jobs are continuing to haemorrhage from the area.
“The reality is this will only contribute to the decline in employment prospects in Blackpool and the continued devastation and decline of the local economy.
“We have written to, or met with, all five local MPs asking that they raise the issue of the jobs in the DWP, across the Fylde, and will continue to press for the case of employment on the Fylde.
“There have been announcements about additional jobs undertaking Personal Independence Payment (PIP)/ DLA reassessment work.
“We have written to the MPs about this as well regarding the potential numbers of jobs to be allocated to the Fylde area.”
A spokeswoman for the Department for Work and Pensions said the figures quoted by the unions were not ones they recognised.
But she added: “DWP has withdrawn from Norcross and redeployed the vast majority of staff to our Peel Park and Warbreck House sites. This was not a workforce reduction exercise and everyone was offered a job in the local area.
“We are currently recruiting 70 administrative officers as apprentices and a further 20 administrative assistant posts in Blackpool.”