Union leaders will meet British government officials next week amid continued anger over Prime Minister Boris Johnson's plan to axe tens of thousands of jobs in the civil service.
Representatives from the Public and Commercial Services union (PCS) will warn that delays in issuing passports and driving licences will get worse if staff numbers are cut.
The union has warned of strikes in response to Boris Johnson's planned 91,000 civil service job cuts.
PCS general secretary Mark Serwotka said: "Our members are in a state of shock. That the first they heard of these cuts was when it was announced in the media tells you all you need to know about what the government thinks of civil servants.
"Our members, the heroes praised by the government for risking their lives keeping the country running during the pandemic, are now being told their jobs are at risk.
"Our national conference in 10 days will debate taking co-ordinated strike action. If our members weren't angry before, they are now, and rightly so.
"Making cuts will only make things worse, make waiting lists longer for those seeking passports and driving licences, make telephone queues longer for those with tax inquiries.
"We shall fight for every job in the civil service. Not just on behalf of our members, but on behalf of every member of the public who relies on the services they provide."
The PCS will hold talks with government officials early next week and there will also be an emergency meeting of its executive to discuss its response to job losses.